# How to - MK1 Alarm Siren fix



## John-H

*ALARM SIREN FIX- HOW TO*

The alarm siren on the TT (original: 8L0 951 605) has a limited battery life and has given quite a few people trouble. The first symptoms of failure are a series of beeps from the rear - usually on a cold morning or after not running the car for a while. This means the rechargeable Ni-Cd (or more correctly Ni-MH) battery is getting old and can no longer hold it's charge and maintain it's voltage under load.

*Replacement or fix?*

You can either get the dealer to replace it for £140, buy the part yourself (P/N: 8L0 951 605 A) for £70 or buy two replacement batteries from Maplin or the like for £10 total and fix it yourself (Maplin Order Code: BN24B [2 required]) . Your choice.

*Tools*

If you decide to fix it you'll need:

10mm ring spanner or similar 
Dremel saw or junior hacksaw
Soldering iron and solder
Hot melt adhesive gun or similar
Some wire and insulating tape.

*Procedure*

The unit is relatively easy to remove as you can see in Wak's guide:
http://www.wak-tt.com/ttalarm/ttalarm.htm which involves taking the rear light cluster off too.

I found you can get the alarm unit out easy enough through the inspection flap without removing the rear light cluster. You can see it here.










You just need to use a small 10mm ring spanner or similar. Reach round the back and loosen the single nut in the middle of the back of the unit. Once it's loose you can remove the nut with your fingers - be careful not to drop the nut! The Alarm can then be unplugged and removed. You won't be able to see what you are doing but it's amazing what you can see by feeling with your fingers :wink:

Once you have the unit out you need to perform some surgery. The case is made from thick plastic and is welded and sealed extremely well. Basically you need to cut into the plastic case along the weld seam. You can see the line here 20mm from the edge of the speaker opening. For this you can use a Dremel type tool. I used the 25mm diameter circular saw attachment. You could also use a junior hacksaw for a more controlled neater job. Cut along the line but don't cut on the speaker side of the line otherwise you may cut off the bezel and not actually open the case :wink: . Cut about 1mm to the other side of the line away from the speaker opening.










You need to cut about 4mm deep all the way round. I left a little under the connector to act as a hinge - not strictly necessary but the prongs in the connector, which come from the circuit board, need to swing clear of the connector aperture, so it helps.










Here you can see how thick the plastic is. Don't cut deeper than necessary or you will cut through the circuit board support pillars.










The circuit board has two spring contacts which make contact with the battery you can see at the back of the unit. Unfortunately in this case the battery had leaked and corroded the contact and actually unsoldered it from the circuit board. This alarm siren had been dead for some time. If you catch your siren early enough (when it's still beeping) you shouldn't have this problem as the battery will not have leaked.

Watch you don't zap the electronics with static electricity from walking across a nylon carpet or similar. Best to earth yourself by touching a tap or earthed item before handling.










Here you can see the circuit board unplugged and unclipped.










Here you can see typical damage to one of the PCB battery connectors, caused by acid leaking from the battery.










The leaking battery can detach the connector from the PCB if it has been leaking for long. Here you can see that the corrosion has penetrated through to the other side of the PCB. This might just respond to cleaning with IPA and a toothbrush but in some cases the solder joints may need repair.










If the acid has eaten away tracks and components, as in this example after cleaning, the circuit board is beyond easy repair.










As a reference, here's a high resolution image of an undamaged circuit board:









(click the image for full resolution - may be slow):

Now for the thing that causes the problem...

Here's a close up of the Ni-MH battery. There are two of these 3.6V batteries wired in series to give 7.2V. If you can find a readily available source you could just replace them.










Unfortunately I've been informed that the only manufacturer Emmerich, a German company, has ceased trading. Their battery was a 160mAh capacity but in it's later production form had been superseded by a slightly increased capacity 170mAh version. The Full specification was:

Ni-MH three cell stack
3.6 V nominal voltage
160 or 170 mAh capacity
320 mA maximum discharge load current
22.1 mm diameter
11.6 mm height
15.5 gms weight

There is an alternative. These "3V" described nominal 3.6V Ni-MH batteries from Maplin are rated at the same 160mAh and are a suitable equivalent. Maplin P/N: BN24B 3/V150H 3.6V 160mAh










As you can see they are a similar size but a different shape with PCB contact pins. If you use them, you need to remove the old batteries and cut away the plastic that held them, in order to make enough room for the two new batteries.










Make sure you observe the original polarity of the old battery. You need to solder the new batteries in series and solder wires between the new batteries and the two spring connectors on the circuit board. The spring connectors can be unsoldered and removed or cut back to make attaching the wires easier and neater.

The new batteries should be wired in series so that they make one big (twice voltage) battery.









Here's another view: >









Then the overall 7.2V battery needs connecting to the circuit board with the same polarity as the original batteries. Look at the way they were connected. You can see here that the original +ve connection from the old battery is in the lower part of the picture. This must also be the +ve connection from your new battery assembly. The -ve connection must go to the upper of the two PCB battery connections in the picture.










Remember the new batteries will be charged, so it is important not to short them out or allow them to make unintentional contact with the circuit board components. Construct the battery assembly separately and insulate well before gluing to the case and soldering it to the circuit board.

Here the battery has been shrink wrapped in adhesive heatshring tubing. After doing this I filled the exposed ends with hotmelt adhesive to form a seal in case the battery should ever leak in future.










The two PCBcontacts are best having their spring prongs snipped off so two flat pads remain as a good anchor point to solder on the wires (RED = +ve, BLACK = -ve).










You can glue the new battery assembly in place with hot melt adhesive or similar. It should go in the same position as the original batteries so it clears the protruding transformer on the circuit board. The plastic holder for the old batteries can be broken away to make room. Make sure none of the battery contacts are exposed and likely to touch the circuit board or that three pin connector. Adding some insulating material to protect it is a good idea or heatshrink if you can get it.


















You can test the electronics at this stage by plugging in the connector to the car being careful not to allow anything to short out. There should be a slight click from the speaker. If you have "beep on locking" enabled you can test it with this function, or set the alarm off by waving your arm through the window.

If the alarm doesn't work and you have a multimeter, measure the battery voltage. If it's much lower than 7.2V it might need charging, so you could leave it plugged in to see if it recovers. If the voltage is 7.2V or thereabouts it should have worked and this might indicate you had further PCB damage from the acid :? . You could try cleaning again.

Finally, if all is well, the case can be closed up and held together with some hot melt and some tape. Make sure the three prong connector pokes through the connector tube centrally. As good as new :wink:










P.S. If you were unlucky and your unit did not work because the acid damage was too great, ask your local Audi dealer for an old returned unit. They only go into a recycling bin but you can do a much better job than that - have another go and save wasting your new batteries :wink:

View attachment Alarm_Fix_Article.pdf


If your alarm loom connector is also damaged you may need to replace it. This helpful post by Warren shows how:

viewtopic.php?f=2&t=73315&start=258

*Beware* replacements from other VAG cars with different part numbers. Although they may look the same the serial comms message may be different and they may not respond. The original siren for the TT is: 8L0 951 605 or the later 8L0 951 605A

This helpful photograph from sheepshearer shows that the latter version can also suffer from the same problem and be cut open and fixed in much the same way:


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## Hev

Brill write up John [smiley=thumbsup.gif]

Hev x


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## mac's TT

Absolutely fab instructions and pic's John. Don't know if I would have the bollox to attempt it though


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## YELLOW_TT

Great right up John lets hope you get the credit this time m8 :wink:


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## KenTT

Hi John

Yet another excellent write up  .

I still haven't done anything about mine, so after this write up I guess I have no excuse now  .


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## John-H

Thanks. I'd been meaning to do this for ages. Having delved into the alarm siren it's possible to extract a signal to trigger a louder alarm, radio pager etc. The alarm sits on the CAN bus so can be used as a simple interpreter from serial CAN data to logic level with a bit of jiggery pokery :wink:


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## Adam RRS

would it be possible to start up a part exchange (as you know what yr doing) and we pay you a sum of money for your troubles?


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## RobLE

Adam TTR said:


> would it be possible to start up a part exchange (as you know what yr doing) and we pay you a sum of money for your troubles?


Exactly what I was thinking! 

Do it!


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## John-H

Now, I can see what's happening here :lol: :roll: :wink:


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## aidb

A brill 'how to' John. Thank you for going to so much trouble. 

You know, selling your alarm refurb expertise wouldn't be a bad idea. :wink:


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## JAAYDE

You are the man [smiley=thumbsup.gif]

I was waiting for someone to finally post this.... :wink:


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## pimpster

what a brilliant post! Maybe one of the mods can either make this a sticky, or put it in the faqs? Or even Wak could link it from his page?


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## Chip_iTT

John-H said:


> Thanks. I'd been meaning to do this for ages. Having delved into the alarm siren it's possible to extract a signal to trigger a louder alarm, radio pager etc. The alarm sits on the CAN bus so can be used as a simple interpreter from serial CAN data to logic level with a bit of jiggery pokery :wink:


John, see you finally got round to it... good one!

you didnt happen to sketch out the circuitry when you had it open by any chance?


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## John-H

Hi Irving,

I've not done that yet but I intend to, in order to use the siren as a trigger for something else :wink: I was intending to find a logic level signal to tap out. Unfortunately there was quite a lot of acid damage and the ink was erased from the resistors etc. I'd like to get hold of another one to experiment with and to scan front and back of the PCB.

If anyone else would like to donate one that's still giving the warning beeps (not one that's been dead for years as that will likely have leaked) I could scan the PCB and repair it at the same time. Send me a PM :wink: .


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## Chip_iTT

John-H said:


> Hi Irving,
> 
> I've not done that yet but I intend to, in order to use the siren as a trigger for something else :wink: I was intending to find a logic level signal to tap out. Unfortunately there was quite a lot of acid damage and the ink was erased from the resistors etc. I'd like to get hold of another one to experiment with and to scan front and back of the PCB.
> 
> If anyone else would like to donate one that's still giving the warning beeps (not one that's been dead for years as that will likely have leaked) I could scan the PCB and repair it at the same time. Send me a PM :wink: .


As you may know I worked up the signalling sequences from the central locking module to the alarm - its not CANBus by the way but a simple bi-directional serial bus - witha view to replicating it but clearly if there *is *a suitable internal signal... however the siren drive itself wont be any use as this is used for too many things (alarm, armed chirp, batt low warning, etc) from the pics this looks like a low-end microcontroller with a MOSFET driver for the siren itself and a simple charging circuit...


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## John-H

Chip_iTT said:


> John-H said:
> 
> 
> 
> Hi Irving,
> 
> I've not done that yet but I intend to, in order to use the siren as a trigger for something else :wink: I was intending to find a logic level signal to tap out. Unfortunately there was quite a lot of acid damage and the ink was erased from the resistors etc. I'd like to get hold of another one to experiment with and to scan front and back of the PCB.
> 
> If anyone else would like to donate one that's still giving the warning beeps (not one that's been dead for years as that will likely have leaked) I could scan the PCB and repair it at the same time. Send me a PM :wink: .
> 
> 
> 
> As you may know I worked up the signalling sequences from the central locking module to the alarm - its not CANBus by the way but a simple bi-directional serial bus - witha view to replicating it but clearly if there *is *a suitable internal signal... however the siren drive itself wont be any use as this is used for too many things (alarm, armed chirp, batt low warning, etc) from the pics this looks like a low-end microcontroller with a MOSFET driver for the siren itself and a simple charging circuit...
Click to expand...

It's not the CAN bus? I didn't investigate - I presumed it was. No matter. It's either chirp, beeps (low batt) or alarm. Even if the siren signal is the only signal available, a monostable with the right attack/decay could be rigged to only trigger from a genuine alarm I think.


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## kam

Changed mine today, only my original batteries are N3H 170. The replacements are slightly higher than the originals.

Removed the rear light as this gives you room to reach the bolt for the alarm. Just taped the cover shut with gaffer tape.

Cheers John, great post :wink:


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## p1tse

always enjoy the how to threads
great write up and pics for future reference


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## gt russell

fab write up john ,as always


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## El Greco

Hi John and thanks for the write up. I attemped to fix my alarm today, all went well but the old batteries had been leaking for so long they had corroded the PCB so my attempt was a failure. Still I had fun with my new soldering iron.
Cheers


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## R6B TT

Super write up John


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## John-H

El Greco said:


> Hi John and thanks for the write up. I attemped to fix my alarm today, all went well but the old batteries had been leaking for so long they had corroded the PCB so my attempt was a failure. Still I had fun with my new soldering iron.
> Cheers


Such a shame  You could always ask your friendly Audi dealer to give you an old one that's been replaced under warranty. They usually scrap them in the recycling bin but with your new soldering iron you could do a better job of re-cycling it :wink:


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## dannys1

can i just ask i stupid question.

Is this for the alarm siren itself - for if someone breaks in or something moves inside, or is it for the "bleep" when you press to lock the car?

The reason i'm asking is because my car doesn't make any "beep" when i lock it, and its actually hard to know if its been done or not (why the hell do the indicators flash once when you lock it and twice when you unlock it, it should be the other way around)

If its for the actual alarm siren itself, i guess i should attempt locking myself in to see if i can set the alarm off to see if mine is still actually working.


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## JAAYDE

dannys1 said:


> can i just ask i stupid question.
> 
> Is this for the alarm siren itself - for if someone breaks in or something moves inside, or is it for the "bleep" when you press to lock the car?
> 
> The reason i'm asking is because my car doesn't make any "beep" when i lock it, and its actually hard to know if its been done or not (why the hell do the indicators flash once when you lock it and twice when you unlock it, it should be the other way around)
> 
> If its for the actual alarm siren itself, i guess i should attempt locking myself in to see if i can set the alarm off to see if mine is still actually working.


leave the windows down lock the car wait 30seconds and stick your hand in... :wink:


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## dannys1

JAAYDE said:


> dannys1 said:
> 
> 
> 
> can i just ask i stupid question.
> 
> Is this for the alarm siren itself - for if someone breaks in or something moves inside, or is it for the "bleep" when you press to lock the car?
> 
> The reason i'm asking is because my car doesn't make any "beep" when i lock it, and its actually hard to know if its been done or not (why the hell do the indicators flash once when you lock it and twice when you unlock it, it should be the other way around)
> 
> If its for the actual alarm siren itself, i guess i should attempt locking myself in to see if i can set the alarm off to see if mine is still actually working.
> 
> 
> 
> leave the windows down lock the car wait 30seconds and stick your hand in... :wink:
Click to expand...

and if i hear nothing - i need to attempt the fix above i guess


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## JAAYDE

yep thats it...

mine went, i did what i just told you all i got was my indicators flashing and no audio only the relay for the indicators ticking...

:wink:


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## dannys1

Interesting i'll try it tomorrow when people are awake! (its bound to not work on mine, along with the other 10 problems ive got...sigh)

out of interest, when you lock the car with the remote, it is supposed to make a single beep then?


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## JAAYDE

dannys1 said:


> out of interest, when you lock the car with the remote, it is supposed to make a single beep then?


Mine never has, neither has it auto locked at 15mph.. You can add these features via the VAG-COM software..


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## YELLOW_TT

dannys1 said:


> Interesting i'll try it tomorrow when people are awake! (its bound to not work on mine, along with the other 10 problems ive got...sigh)
> 
> out of interest, when you lock the car with the remote, it is supposed to make a single beep then?


If it does work the standard alarm is very quiet 
No you have to set the beep up using vag com


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## dannys1

I just tested this morning - it does work, but your right, it really is quiet. Its less of a siren and more of a beep!


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## mordred1973

typical....2months out of warranty and what do I get....the beep from the rear....not sure I'm brave enough to go cutting the unit up...

you'd think Audi would make it last longer than 3 years!


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## El Greco

Well I got hold of a second hand alarm.The alarm arrived this morning, I connected it up but still no sound? Could there be any other problem or just the batteries. The lights flash and when i connect the siern there is a slight click from the speaker. any advise would be apprieciated.  
Cheers


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## John-H

I'd say that if you hear some clicking then it's trying to sound but can't. So the communications is getting to the siren and it's not your car at fault. It could be the battery is flat and might work once charged. Could be the batteries are just dead or at worst leaked over the PCB inside. I'd leave it for a while to charge, then if it doesn't start to work, it might need taking apart to investigate a possibl repair - or complaining to the seller :? .


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## JAAYDE

wow don't blame the seller... :roll:

His unit is working now... 

It just needed to charge of the car battery (a quick drive)


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## El Greco

All sorted now. I had already bought the batteries for my old unit so decided to do a battery change in this unit just in case. All working as it should be but it's pathetic! I cant believe Audi can design an alarm which would be better suited to an alarm clock!! I hope any would-be burglars open the boot up as it's slghtly louder then.

Cheers


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## John-H

El Greco said:


> All sorted now. I had already bought the batteries for my old unit so decided to do a battery change in this unit just in case. All working as it should be but it's pathetic! I cant believe Audi can design an alarm which would be better suited to an alarm clock!! I hope any would-be burglars open the boot up as it's slghtly louder then.
> 
> Cheers


Glad you got it sorted  . By the way, what batteries did you get as replacements - where they the ones I suggested from Maplins or did you manage to find a source of battery that fits in the existing moulding? - I'd be interested and it would make the job easier for others. The original manufacturer no longer exists and they were single sourced apparently :?


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## Captain Beeflat

Superb...Exactly what this forum needs. Shall have to organise a file in which to keep all this "just in case" information. Well done John.


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## Rhod_TT

Quick question. Can I remove my alarm siren unit and drive the car around ok or is there some electrical check that it will fail? Want to take the unit out tomorrow but won't be able to get batteries until later in the week. Car is garaged most of the time but I'd like to know if I could drive it if I have to.


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## JAAYDE

Rhod_TT said:


> Quick question. Can I remove my alarm siren unit and drive the car around ok or is there some electrical check that it will fail? Want to take the unit out tomorrow but won't be able to get batteries until later in the week. Car is garaged most of the time but I'd like to know if I could drive it if I have to.


Alright chap..

It will only throw a fault up in the vag-com but the car will run fine (no lights on dash etc)

:wink:


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## bobdabuilda

is there a mod to the existing alarm unit that will increase its volume or a direct swap alarm unit that can plug in in its place?


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## John-H

When I get time I'm going to investigate that idea  . I think the best possibility is tapping out a signal that changes state when the alarm is triggered. This could be linked to a transistor or relay and used to drive another horn... perhaps this one: http://www.filecabi.net/host/file/ferryhorny/wmv


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## l3ttx

Great post john, just been out to my car tonight to put it to bed and heard beeps from the back, now do you think its just the cold or the batteries going. Or am i going to maplins tomorrow :wink:

mines a late 2002 225 coupe.


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## Rhod_TT

Replaced my faulty batteries with Maplin ones last weekend (did look for other batteries but found nothing suitable). Works a treat now (well actually I don't know - it no longer beeps from the rear when I start the car - but still beeps when I lock it).


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## John-H

Rhod_TT said:


> Replaced my faulty batteries with Maplin ones last weekend (did look for other batteries but found nothing suitable). Works a treat now (well actually I don't know - it no longer beeps from the rear when I start the car - but still beeps when I lock it).


Excellent. Sounds OK then - you could always lock your car and wave your hand in through an open window to test the alarm  .


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## bobdabuilda

what is that new design alarm unit on WAKS how to thread? It looks different to the one he replaces.... is it a better/louder one?


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## TTCool

John

Excellent writeup and pics, as usual. I'm almost wishing mine would break :lol: NOOOOOOOOOOOO 

Joe


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## bobdabuilda

If I could find a scrapped audi tt could I just swap the alarm unit with my cars dead one?? Or is it coded to the car somehow??


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## JAAYDE

bobdabuilda said:


> If I could find a scrapped audi tt could I just swap the alarm unit with my cars dead one?? Or is it coded to the car somehow??


you can straight swap it, thats what i have done.. :wink:


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## John-H

bobdabuilda said:


> what is that new design alarm unit on WAKS how to thread? It looks different to the one he replaces.... is it a better/louder one?


bobdabuilda,

I guess they just redesigned the case to accommodate a new battery since the previous one became unobtainable. No louder I believe - and yes, there's no unique coding to the car.

Joe,

Cheers


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## bobdabuilda

JAAYDE said:


> bobdabuilda said:
> 
> 
> 
> If I could find a scrapped audi tt could I just swap the alarm unit with my cars dead one?? Or is it coded to the car somehow??
> 
> 
> 
> you can straight swap it, thats what i have done.. :wink:
Click to expand...

Thanks- is there an online scrapyard that I can email to see if one is available?


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## JAAYDE

bobdabuilda said:


> JAAYDE said:
> 
> 
> 
> 
> 
> bobdabuilda said:
> 
> 
> 
> If I could find a scrapped audi tt could I just swap the alarm unit with my cars dead one?? Or is it coded to the car somehow??
> 
> 
> 
> you can straight swap it, thats what i have done.. :wink:
> 
> Click to expand...
> 
> Thanks- is there an online scrapyard that I can email to see if one is available?
Click to expand...

try http://www.hills-motors.co.uk/ they scrap alot of TT's :wink:


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## bobdabuilda

THANKS!


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## bobdabuilda

John-H said:


> bobdabuilda said:
> 
> 
> 
> what is that new design alarm unit on WAKS how to thread? It looks different to the one he replaces.... is it a better/louder one?
> 
> 
> 
> bobdabuilda,
> 
> I guess they just redesigned the case to accommodate a new battery since the previous one became unobtainable. No louder I believe - and yes, there's no unique coding to the car.
> 
> Joe,
> 
> Cheers
Click to expand...

So what does the battery setup look like in the new unit design(assuming that this unit will suffer the same fate as the original in due course???)
Any chance of you offering a repair service for these alarms John?? Don't fancy doing all that fiddly soldering etc....then again I suppose there are safety issues to consider and anyone having a repair done would have to sign a disclaimer in case of something going wrong in this pc world eh?!!!


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## John-H

Your guess is as good as mine on the battery in the new one - perhaps mini AA or something - you'd need six 1.2V cells.

I provided the information as is to help others. I didn't really want to get into fixing them on a regular basis. I could see my kithen worksurface covered in the things :lol: . The liability side is another worry of course :roll: .


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## folkswagon

Fantastic write up, used it to start fixing my alarm but found that my battery leakage has completely knackered the circuit board.

Does anyone happen to know a good mail order site for a new one rather than going to the Audi dealer?

Cheers :?


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## John-H

folkswagon said:


> Fantastic write up, used it to start fixing my alarm but found that my battery leakage has completely knackered the circuit board.
> 
> Does anyone happen to know a good mail order site for a new one rather than going to the Audi dealer?
> 
> Cheers :?


Your best bet is to ask your Audi dealer to save you an old one that someone has had replaced - they only throw them into a recycling bin. I did that and got a spare to work with. You could also ask if anyone on the forum is getting a replacement and ask them to send you the old one :wink:


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## bobdabuilda

I can't believe nobody can invent a new improved alarm siren unit for the TT!!! Come on you clever chaps!


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## stevejoy5

amazing write up top thread


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## Chip_iTT

bobdabuilda said:


> I can't believe nobody can invent a new improved alarm siren unit for the TT!!! Come on you clever chaps!


watch this space  but i can't get hold of a good s/hand alarm unit.. had 2 now and both have been beyond repair... anybody care to donate one?


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## mossi

just like to add my thanks, the beeping started a wk ago, drives you nuts ! went and bought the batterys, nd fitted today, all sorted..
nice one 8)


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## karozza

The TT siren seems like a coded siren; if anyone knows or can get a hold of the coded sequence? Maybe I can get a replacement/better siren.


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## kite

Bump
Great how to John.
Just used this to fix the siren on the wifes TTC.
a quick question, if the alarm batts are not made anymore what batts are in newer alarms, if we could find out what they use now perhaps new type batts could be placed in older alarms.....just a thought....


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## John-H

kite said:


> Bump
> Great how to John.
> Just used this to fix the siren on the wifes TTC.
> a quick question, if the alarm batts are not made anymore what batts are in newer alarms, if we could find out what they use now perhaps new type batts could be placed in older alarms.....just a thought....


Good thought but the newer alarms have a different and larger case - I suspect they use a stack of 1/2AA cells or something, which won't fit in the old case.


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## kite

John-H said:


> kite said:
> 
> 
> 
> Bump
> Great how to John.
> Just used this to fix the siren on the wifes TTC.
> a quick question, if the alarm batts are not made anymore what batts are in newer alarms, if we could find out what they use now perhaps new type batts could be placed in older alarms.....just a thought....
> 
> 
> 
> Good thought but the newer alarms have a different and larger case - I suspect they use a stack of 1/2AA cells or something, which won't fit in the old case.
Click to expand...

What a shame


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## 3phase

has any one thought of having the bateries external to the box to stop acid damage when i do mine i will let you know


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## karozza

Has anyone tried extending the wires from the boot to the engine bay & installing the siren under the bonnet? It would defintely be much louder :idea:


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## John-H

There's nothing to stop you having an external battery, although the way I applied heatshrink and hotmelt adhesive should prevent leakage of the replacement battery.

Yes, the wires could be extended I suppose. I've always intended to get round to tapping out a signal to drive an external option - this could be another louder siren, airhorn, radio transmitter etc. The original alarm could remain in place.


----------



## bobdabuilda

John-H said:


> There's nothing to stop you having an external battery, although the way I applied heatshrink and hotmelt adhesive should prevent leakage of the replacement battery.
> 
> Yes, the wires could be extended I suppose. I've always intended to get round to tapping out a signal to drive an external option - this could be another louder siren, airhorn, radio transmitter etc. The original alarm could remain in place.


Do it John!!!!!! That would be awesome! Just imagine if you could program the alarm to play the Darth Vader arrival music......


----------



## John-H

bobdabuilda said:


> John-H said:
> 
> 
> 
> There's nothing to stop you having an external battery, although the way I applied heatshrink and hotmelt adhesive should prevent leakage of the replacement battery.
> 
> Yes, the wires could be extended I suppose. I've always intended to get round to tapping out a signal to drive an external option - this could be another louder siren, airhorn, radio transmitter etc. The original alarm could remain in place.
> 
> 
> 
> Do it John!!!!!! That would be awesome! Just imagine if you could program the alarm to play the Darth Vader arrival music......
Click to expand...

It's a bit early to be drinking this time in the morning isn't it? :lol: :wink:


----------



## karozza

I'll b extending mine to the bonnet once I manage to get a good working used one :!:


----------



## turtleTT

cheers john did mine today spot on how to :wink:


----------



## gloveywoo

I did mine a few weeks ago also. Had some corrosion on the contacts but managed to make a clean contact.

One of those jobs I kept putting off but happy to have done it now 

Thank you John :-*


----------



## SOFTTY

ru you people handy with a soldering gun by any chance as i am not :x


----------



## turtleTT

haha its easy just take your time took me about 30 mins from start to finish trying to make it a tidy job


----------



## Nick 225TT

My Alarm was totaly silent however I went back to the dealers and had a new unit fitted free :lol:

Glad I bought My TT225 approved used


----------



## CHADTT

Got mine fixed under the warranty too.

Alarm was working fine though, however VAG com kept reporting 'Terminal 30 intermittent.

Service manager asked how I knew there was a problem with the alarm!!

Learnt a lot from this forum 

Edit
The original alarm module was the same as the replacement one they fitted. This is the modern version with the larger mounting bolt and looks rectangular, rather than square.


----------



## wicked666

Hi,

I have an 1999 A3 and this beeps at me 4 times when I start the car.

I've looked in the back and I don't have a large siren like the pics, but a small control box and what looks like a doorbell 

I've opened up the box and it looks like the battery has leaked but not 100% sure. This may be a silly question but Audi don't spray anything ontot their circuit boards to protect them do they? Also is it worth me changing the battery or is it too far gone as the PCD is covered in the brown liquid (although it's dry)

Actually looking at Maplins, this appears to be a capacitor - do the older Audi's use a capacitor?


























Cheers


----------



## John-H

That comes up on Etka as a "movement detector" which costs £250 so be careful with it :!: . It's only part of the alarm system but it's not the siren. The large tall item in the corner is actually an electrolytic capacitor for smoothing the supply voltage and not a battery. The brown stuff that looks like it might have leaked is probably a type of sealant glue conformal coating that they often dribble over such items on PCBs in order to make them rigid and not wobble on the PCB and to stop moisture causing a problem. When tall capacitors wobble with vibration, the solder joints can fail through metal creep and fatigue so making the item rigid to the PCB stops this.

Carefully put it back the way it was :wink:

To find the alarm siren, lock the car with the windows open and wave your arms inside to set off the alarm - then trace the sound.


----------



## easy6

Ha John
Got the 4 beeps from what seemed from the back of a 2000 model TTQ.
So after reading your great write up got the replacment batteries made up same as yours.
Next went to car and removed the light assembly ....only to find no alarm siren?
Also no harnes.. but what seems to be a threaded bolt where I imagin the alarm was bolted to the inergarde.
This has never been used as the paint still covers the thread.
Ok where is the 4 beeps comeing from?
Windows open car alarmed, wave inside all hell breaks loose with an activater alarm. :roll: 
Ok maybe Australian models are diffrent..........but those bloody 4 beeps.
Any help before I spit the [smiley=baby.gif]


----------



## John-H

Well, that is odd. But where does the alarm sound come from? As far as I know it's the European models that have the siren (with its internal back up battery) in the back wing but US models employ a Horn sounder under the cover over the windscreen wiper mechanism below the windscreen. There seems not to be any mention of an alarm back up battery for these models in the wiring diagram - it just shows a connection to the horn sounder. This horn _looks_ like a standard electro-mechanical horn and not an electronic siren. The electronic siren in the European models has a back up battery so that the siren can continue even if the main car battery is disconnected. To keep an electro-mechanical horn operating the back up battery would have to be much bigger as the required current is much higher.

Perhaps you could verify the nature of your alarm sounder - when you set it off does it sound like an electronic siren type device or more like a car horn?

If you set off the alarm, then disconnect the main car battery, does the alarm horn stop sounding? This would confirm there is no back up battery - which I can't see any documentation for (If you do this remember to have the radio code and reset your windows).

So, I don't know what your warning beeps are - perhaps they are something completely different? Or perhaps it is an electronic version but it's mounted elsewhere? Try tracing the sound.


----------



## wicked666

Cheers for the info! I'll put the movement sensor back - glad I asked before trying the clean it up with IPL!

I'm the same is that I can hear the beeps when I lock the door, but can't find out where it's coming from. I'm sure it from the small speaker that's mounted there - will get onto etka and try and see where this connects to.

Been on ETKA and got this!










The small speaker that's in the rear is the parking aid - however it beeps when I lock the doors and beeps 4 times so thought it was the same thing! I do not recall seeing the speaker in the engine bay but will check a bit later today.

Cheers guys


----------



## wicked666

Ignore the above diagram, its wrong. found the sounder right down the bottom, behind the rear bumper. Will get onto the fix now


----------



## easy6

Thanks John
Ok when the alarm goes of the sound comes from the front of the car under the bonnet,sounds like the horn.so your saying when yours goes of it's from the rear.
So mine must be like the US model. Got onto tt forum US & they get the 4 beeps to???????
Maybe my car battery is on its way out?
Anyway thanks John.I'll keep [smiley=book2.gif]


----------



## John-H

easy6 said:


> Thanks John
> Ok when the alarm goes of the sound comes from the front of the car under the bonnet,sounds like the horn.so your saying when yours goes of it's from the rear.
> So mine must be like the US model. Got onto tt forum US & they get the 4 beeps to???????
> Maybe my car battery is on its way out?
> Anyway thanks John.I'll keep [smiley=book2.gif]


Let us know when you find where it's coming from.


----------



## KentishTT

Hi John;

Do you know whether the EU model TT with the siren in the rear wing can have a secondary alarm siren added to it?

Is there a driver for the alarm sounder?

It's so pathetically quiet tucked inside the rear wing and I'd like to add something a bit louder and weather proof outside somewhere.

Cheers,
Kevin


----------



## John-H

Something I've been meaning to do for a while Kevin. The siren in the rear is triggered by serial comms from the central locking controller, so there's no simple on/off signal. There may however be a possibility to tap off a signal _inside_ the siren, after the serial data has been translated into an analogue signal, in order to drive a relay or whatever :wink:


----------



## KentishTT

It's a longshot but if there's ever a weekend when I'm not busy I may well have a look into doing this :wink:


----------



## bobdabuilda

did you ever get that weekend fix done? :?


----------



## s3mad

If anyone wants to have a siren to muck about with i have one as i have replaced mine out of my s3 ,

let me know before i chuck away . Also has anyone managed to get a aftermarket siren to work aswell as standard audi one ?


----------



## Guest

Quick question..... Is the alarm supposed to beep when you lock the car, i have no idea whether mine works or not.... :? what's the best way to check? Lock yourself in the car?


----------



## s3mad

Lock the door u inside then wait 30-1min and wave your hands about like you just dont care !!

and then you will hear a alarm clock go off dont jump out your seat


----------



## was8v

On my TT 225 the alarm is silent - the indicators flash when setting it off tho.

Is this a symptom of a dead siren battery? Or will the battery have leaked and killed the siren totally?

If the battery was dead I would think it would draw power from the the main car battery. Or does it not work like that?

Cheers.


----------



## scott_159

mine is exatly the same!

i took mine apart after ordering some batterys from rs but the battery had leaked everywhere and totaly killed the board!

time for a clifford


----------



## was8v

scott_159 said:


> mine is exatly the same!
> 
> i took mine apart after ordering some batterys from rs but the battery had leaked everywhere and totaly killed the board!
> 
> time for a clifford


Hmm theres quite a few on ebay.de for around 30 euro plus delivery, but they are used and may not last too long. But I suppose then you could just put new batteries in when it starts chirping.

I might pull mine apart first to see what its like, but I suspect it will be ruined if it has stopped chirping completely.


----------



## Il Signor Zetec

How is it possible to put this type of siren when it's disconnected from the car? If the internal battery has a low charge, the siren can chirp the same?
I bought one from ebay but it seem to don't work..


----------



## Il Signor Zetec

nobody can help me??? [smiley=bigcry.gif]


----------



## was8v

If a second hand one doesn't work its likely the internal battery has leaked destroying the circuit board.


----------



## Il Signor Zetec

I opened it and all was ok! No acid, perfect circuit and the battery was over 8 volts! Unfortunately, making test with the tester...I burned some components!
Can you tell me how can I test it (when I bought another one) with a 12V battery out of the vehicle?










I tried to connect wire 1 to earth, wire 3 to permanent positive and wire two to a positive to simulate a alarm signal...is it ok??
thank you
Luca


----------



## was8v

NO!!!!

The siren works by a serial communication link. If you go connecting 12v about you will likely blow some components.

I don't know the pinout, but theres likely a + and - and at least one link wire. The working voltage may be less than 12v so be careful!

Best to connect it to the car and see if it works!


----------



## Il Signor Zetec

But...now on my car I have a simple horn instead of the siren! It has a permanent earth and a cable for the signal alarm...si I supposed it was a positive! [smiley=bigcry.gif]


----------



## was8v

I have just bought a new model used siren from:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0311667036

Works out at £41.22 in total delivered to the UK (14.90€ delivery). The listing says they are fully tested so will let people know how I get on when it arrives. The batteries won't last as long as a new one but I can do the battery replacement when / if they wear out and it still works out a bit cheaper than a new unit from Audi.


----------



## Il Signor Zetec

this is the same seller when I bought mine! He's serious.
So, referring to the image posted by me, the wire 1 is earth, the 2 is the serial communication and 3 is a permanent positive?


----------



## Il Signor Zetec

Must the siren being activated via vag-com when I put it on a car that had a horn instead of a siren? Do you have on yours TT vag code a specific one for the activation of the siren?
Also another siren doesn't work in my car... [smiley=bigcry.gif]


----------



## was8v

Il Signor Zetec said:


> Must the siren being activated via vag-com when I put it on a car that had a horn instead of a siren? Do you have on yours TT vag code a specific one for the activation of the siren?
> Also another siren doesn't work in my car... [smiley=bigcry.gif]


Hmm.

Lock the car with the keyfob with the window open. the lights ins the door should flash quickly for 30 secs or so, then slowly.

Now wave your arms in the car. This should set the alarm off. Your indicators should flash and the alarm sound.

If nothing happens then you must ahve a fault.

When i had a faulty siren, VAGCOm reported "faulty communications to alarm siren" or similar.

Now with a working siren it reports no errors.


----------



## Il Signor Zetec

I did this test, but I can see only the light flash fast when the alarm goes on! No sound from the siren, also when I activate the alarm!
The vag doesn't report any error...
Is there a vag code to tell to the central locking ecu that you stay in England??? :?:


----------



## was8v

Il Signor Zetec said:


> Is there a vag code to tell to the central locking ecu that you stay in England??? :?:


No idea!

Well if the alarm system appears to be otherwise working (lights flash), I'd say it must be something to do with the connection to your siren or your siren.

Can you test your siren in another car?

Maybe worth tracing the loom back from the alarm siren to wherever it goes and checking for continuity.


----------



## Il Signor Zetec

I can't test a siren on another audi.
If I disconnect the siren and I reconnect the old horn, all work normally! The horn goes on with no problem (and with its horrible sound...) [smiley=bigcry.gif]


----------



## was8v

Il Signor Zetec said:


> I can't test a siren on another audi.
> If I disconnect the siren and I reconnect the old horn, all work normally! The horn goes on with no problem (and with its horrible sound...) [smiley=bigcry.gif]


I susopect you have a broken siren unit then. Try another?


----------



## kkslavov

Hi all electronics gurus,

i just replaced my battery with 7.2v 200MAH, but unfortunatelly i can hear extremely 
quiet siren. It so so hard to hear it that i needed to put my ear on it to hear it.

Something is wrong for sure. I hope i didn't burn something, but most possibly I have.

I assume that the MOSFET is not dead because there is no visible damage on it. I heard that when they burn they
make a hole or melt or something that i could say it is dead just eyeballing it.

If anyone have any ideas, please.

Otherwise the alarm and the siren is responsive to the commands. Chirps on lock, on panick mode also. But it is just extremely quiet. I mean not as before I have replaced the battery.

Thanks


----------



## CHADTT

Dont think I've seen a panic mode. How does that work?


----------



## kkslavov

Well, just push the red button on the side of the alarm remote and hold it for a second.


----------



## John-H

kkslavov said:


> Hi all electronics gurus,
> 
> i just replaced my battery with 7.2v 200MAH, but unfortunatelly i can hear extremely
> quiet siren. It so so hard to hear it that i needed to put my ear on it to hear it.
> 
> Something is wrong for sure. I hope i didn't burn something, but most possibly I have.
> 
> I assume that the MOSFET is not dead because there is no visible damage on it. I heard that when they burn they
> make a hole or melt or something that i could say it is dead just eyeballing it.
> 
> If anyone have any ideas, please.
> 
> Otherwise the alarm and the siren is responsive to the commands. Chirps on lock, on panick mode also. But it is just extremely quiet. I mean not as before I have replaced the battery.
> 
> Thanks


The way it works is for a logic level signal from the processor to drive the MOSFET gate and turn it on and off rapidly. The MOSFET drives the transformer which steps up the voltage to drive the pietzo sounder. The MOSFET driving the transformer is a MTD3055VL http://www.fairchildsemi.com/ds/MT/MTD3055VL.pdf . One mode of failure for the MOSFET is for the case to get holed if the die gets too hot but they can fail without rupturing the case. They can get a ruptured gate if more than 20V is applied and look fine as that's just voltage breakdown and not excess heat, which can be due to static discharge.

If the transformer is not damaged then I'd suspect the drive to the MOSFET or the MOSFET itself. Check the components connected to the gate, between the gate and the processor. There may be corrosion damage partially shorting or disconnecting the signal. If the sugnal is not a full 5V logic signal, but instead a reduced weedy little one, then the MOSFET will not turn on properly. This may explain the low volume. Use an eyeglass to closely inspect the components. Sometimes corrosion can eat away the metalisation on the ends of the resistors , for example, but they otherwise look OK.

The best method would be to trace the signal with an oscilloscope but a multimeter may help with a little interpretation. A 5V square wave will measure 2.5V if the on and off period is equal etc. If the gate signal is good then I'd suspect the MOSFET, but check the transformer coils for continuity as it's possible corrosion could have eaten something away.

I hope that helps.


----------



## kkslavov

Actually I did unsolder the transformer from the board to clean underneath it. There was too much acid spread all over the board. I will check the transformer again connections to the board. That's all that I could possibly test on the transformer. Any characteristics for him, just in case I need to buy one?

As far testing the MOSFET and the gate voltage. Should I test it while it is connected to the car to test the input voltage to the gate ? or I could apply directly 5V on the gate. The example you are giving is to apply 5V square wave on the middle input pin of the siren - the signal, and check the gate voltage to be 2.5V on and off?

Thanks,


----------



## John-H

The transformer is going to be a step up type, so the primary (input) will be a low number of turns with thicker wire, and the secondary (output) is thinner wire with a much higher number of turns. The ratio of the number of turns PRI:SEC determines the increase in voltage. e.g. 25:1 would transform 5V (PRI)to 125V (SEC).

The transformer can fail in three main ways:

1) Broken winding - where the acid may have eaten through the wire. The secondary (output) is more prone as the wire will be thinner. This simply disconnects the output.

2) Shorted turn - where the insulation has been eaten away and one or more turns in a primary or secondary winding are shorted together forming a short circuit loop - all the current will flow in this loop and there will be no output on the main terminals.

3) Short between primary and secondary or to core. Not too important in this design as the output is floating relative to the input.

1) Can be tested with a multimeter set to ohms. Expect the primary to be around a low ohm or two and the secondary to be much higher, perhaps one or two hundred ohms at a guess. If either are open circuit hen you know a winding is broken.

2) Is more difficult to test as the multimeter will not show it up or even if it did show up a difference you won't know what to compare the reading to. A proper test would be to inject an AC signal into the primary and measure the output. This is what the alarm circuit does however, so what you could do is get it working, with the alarm sounding, and set your multimerter to AC Volts and measure the voltage on primary and secondary. If you get some voltage on the primary and nothing, or far lower,on the secondary, then because you previously determined that test 1) is OK then you know that the transformer is not doing its job.

One other point is that with a shorted turn, the transformer will heavily load the primary drive circuit (MOSFET) and so the voltage across the primary will likely be much lower than it should be and the MOSFET will get hot. If the voltage is low but the MOSFET doesn't get hot, then it would appear that either the MOSFET isn't switching or the drive to the gate is not working. So concentrate on the gate drive and MOSFET.

Don't apply 5V direct to th eMOSFET gate as if it turns on continuously it will conduct a huge current through the primary winding, which is a low DC resistance but a much higher impedance if driven with AC like it's meant to. Just measure the DC voltage coming out of the processor and trace it along through each component up to the gate of the MOSFET. It may help draw out the circuit as best you can and then after making a number of voltage measurements it may become obvious which component has failed. If the MOSFET gate has shorted its thin oxide layer to drain or source, then there will likely be no signal on the gate. You could lift the gate pin and use a multimeter to test it is still insulating (infinity ohms) but be careful to ground yourself and equipment as static charge can blow an unprotected MOSFET gate. You can generate thousands of volts by walking across a carpet and the gate can only withstand up to 20V.

Hope that helps. Good luck


----------



## bobdabuilda

Did anyone ever get around to finding out whether an aftemarket alarm mod would work? Seems like a very important and no doubt would be a popular mod with owners

PS pm me if you know of a working one for sale anywhere!


----------



## S&amp;S

Howloaud is this bleeping? mine is making a siren from the boot, bleeps for a while stops then carries on, stops ect

No lights flashing or anything, do i need to replace the batteries?


----------



## b8yd k

I removed my siren with the idea of repairing and my car battery went flat pretty quick. Any ideas if this is just coincidence of is missing siren meaning ecu or something is staying on after Ign off.

Any ideas?

Also what if I just remove batteries? I know it wont be backed up, but it should go off still when main car battery is connected.


----------



## b8yd k

Just plugged it back in with no batteries and the siren now works and it's pretty loud, wouldn't want to be in the car with that going off.

I will get round to doing the batteries in the next week or 2, but just thought you want to know that it works without the batteries even being fitted.


----------



## 4UDI TT

The alarm is suppose to make a noise? Well i never

Shipped my TT from the UK to NZ several years ago and have never heard the alarm go off. Then i found this forum, thought i wonder and tested the alarm. Sure enough, the lights flashed but no noise. Took out the cute black box, sliced it open and found......... corrdoded batteries and a circuit board which had gone organic, lovely green stuff growing everywhere. Think this one is well and truely knackered.

Popped down to my local friendly (NOT [smiley=argue.gif]) Audo garage and enquired of the nice gentlemen there, the price for replacement of said alarm siren, having first enquired whether Audi offered a 'goodwill' free replacement on a product that was obviously of such inferior quality that they must have been installed in Audis by gremlins at the factories in eastern europe. Funny, these guys didn't have a sense of humour and said they have never heard of problems with the alarms, no surprise there then. Then they told me the price, in one fell swoop the smile on my face was gone and the red mist descended :twisted:

$371NZ.

I'll say again, $371NZ - that's about 150 quid.

Pause, long pause, deep breath, food for family/alarm for car? OK, i'll have it in black i said. Again, no sense of humour these guys.

I am now the proud owner of a new alarm system courtesy of your friendly Audi dealer. He smiles at me now because he has all my money. The alarm unit has been re-shaped, still in beautiful black plastic but, it looks as if the unit can be opened without the need to dice and slice. Probably to make it easier to replace the next lot of corroded batteries. Oh joy.

Now to try the alarm out on the neighbours [smiley=cheers.gif]


----------



## TTCool

Good morning

What the TT needs is a proper after market alarm. Now there's a thought. Has anybody fitted an after market alarm which does the job that most, if not all alarms do, on other marques? If so, can we please cut to the chase and solve the problem for good. If it's about price, I paid £75 for my new unit and fitted it myself; a simple job. That surely compares favourably with the cost of bling.

In my experience some after market alarms can cause problems and the TT might surely be a prime example, hence the request for an after market alarm which has been tried and tested on a TT and not found wanting.

I do acknowledge that there is a certain satisfaction in fixing things. Come on John, slap me down

Joe


----------



## bobdabuilda

It does seem crazy that nobody currently does an aftermarket alarm system for the TT when there is clearly a demand. :?


----------



## aleach1728

Great write up, and with some free time on my hands decided to have a go being as my alarm does not work and nothing to lose.... so out the black box came  disappointed to find out my battery had leaked all over the circuit board and was knackerd! I phoned derby audi up and they wanted £75 for a new siren box and asked about the recycled siren boxes and they did not have one  atleast the trusty hazard lights work instead lol


----------



## bobdabuilda

aleach1728 said:


> Great write up, and with some free time on my hands decided to have a go being as my alarm does not work and nothing to lose.... so out the black box came  disappointed to find out my battery had leaked all over the circuit board and was knackerd! I phoned derby audi up and they wanted £75 for a new siren box and asked about the recycled siren boxes and they did not have one  atleast the trusty hazard lights work instead lol


I did the same. 
Still wish somebody would bring out a cheap alternative as these recycled siren boxes are like hens teeth and no doubt mostly knackered! There must be some clever sparkytech chaps oot there?


----------



## Bikerz

No matter how good the eleronics guy was. The acid in the battery will haev eaten into the lines on the board requiring a new board. I could design a copy but I dont have the facilities to make "dip" them.

Sheldon
(Electrical & Electronic Engineer)


----------



## Cronas

Mine is the same, just tested it. Flashing lights but no sound 

what is recommended? perform this fix or get a better alarm? I have never heard the TT alarm but if it is true what everyone here is saying, whats the point of fixing it if you won't hear it anyway?


----------



## mattshields2004

If its just the siren that is rubbish, why not buy a siren from another alarm system, like toad or clifford. At the end of the day, its only a speaker with two cables. Surely it is possible?


----------



## Cronas

mattshields2004 said:


> If its just the siren that is rubbish, why not buy a siren from another alarm system, like toad or clifford. At the end of the day, its only a speaker with two cables. Surely it is possible?


I'm not sure on this but I am guessing it is to do with volatage? I had a brief look for them and they appear to be 12v which would mean connecting to the battery but the current one is using 7.2v

Is this correct?


----------



## Stu225

Cronas said:


> Mine is the same, just tested it. Flashing lights but no sound
> 
> what is recommended? perform this fix or get a better alarm? I have never heard the TT alarm but if it is true what everyone here is saying, whats the point of fixing it if you won't hear it anyway?


go to a scrap yard i got one from a Skoda Octavia works a treat


----------



## Cronas

Stu225 said:


> Cronas said:
> 
> 
> 
> Mine is the same, just tested it. Flashing lights but no sound
> 
> what is recommended? perform this fix or get a better alarm? I have never heard the TT alarm but if it is true what everyone here is saying, whats the point of fixing it if you won't hear it anyway?
> 
> 
> 
> go to a scrap yard i got one from a Skoda Octavia works a treat
Click to expand...

Is it loud? does it fit in the same place as the TT one? how much di you end up paying?

Many Thanks


----------



## lazerjules

If anyone has a dead circuit board they don't want, perhaps you would be happy to send it to me. I will have a look at copying it and making some new boards.

PM me if anyone is interested.


----------



## lazerjules

Hmm, after looking at some of the pics of the PCB, it looks like the large chip is some sort of obsolete processor.
First problem, its obsolete, second problem, if it's programmed then there is very slim chance of extracting the code.
Might be more difficult than I first thought.

Will dig around a bit more though.


----------



## HAZE_87

If anybody is looking for the battery used in this alarm system, then you can get it from this battery site http://www.cellpacksolutions.com/Search_Data_Sheet.asp?ID=3/V150H/2P


----------



## harrismhome

Hi

Can anyone tell me where to get the I think it's a transformer shown in the picture the dreaded acid has eaten the connections but the pcb is as new thankfully the transformer? has "EPCOS PRC MN F005 V 0109" written on it.

tx

Mark


----------



## John-H

The transformer will likely be a custom wound step up transformer needed to create a high voltage to drive the pietzo sounder. Getting a replacement may be difficult. How badly are the connections eaten away? If you can part disassemble it and find the winding ends you could solder on some new wire or pins. If the inner end has been eaten away so you can't get at it, then it is possible to unwind the coil and start again. It is fiddly though. If you count the number of turns you can at least find out the ratio of turns and ultimately make a new one. You could also get a spare from someone else's broken siren or you may find an equivalent transformer in a similar piece of equipment i.e. another pietzo siren e.g. house/car alarm etc.


----------



## KentishTT

Does the alarm siren box have any functionality other than taking a signal and increasing it to drive the piezo electric siren built into the box?


----------



## John-H

KentishTT said:


> Does the alarm siren box have any functionality other than taking a signal and increasing it to drive the piezo electric siren built into the box?


The siren contains a processor that both drives the circuitry for driving the transformer and siren but also handles the serial communication to the CAN bus, so when the central locking controller decides that the siren should make a noise it sends out an addressed data packet which tells the siren what to do. That's why it's not easy to add a louder siren - as you need to interpret the serial bus. Once you have the original unit apart however you could potentially run extensions to the transformer to another pietzo sounder mounted elsewhere or some other interface - using the original processor for hadling communications as normal.


----------



## harrismhome

John-H said:


> The transformer will likely be a custom wound step up transformer needed to create a high voltage to drive the pietzo sounder. Getting a replacement may be difficult. How badly are the connections eaten away? If you can part disassemble it and find the winding ends you could solder on some new wire or pins. If the inner end has been eaten away so you can't get at it, then it is possible to unwind the coil and start again. It is fiddly though. If you count the number of turns you can at least find out the ratio of turns and ultimately make a new one. You could also get a spare from someone else's broken siren or you may find an equivalent transformer in a similar piece of equipment i.e. another pietzo siren e.g. house/car alarm etc.


Hi John,

That's what I was planning to do is get the tails out of the windings, would have worked for the thicker gauge winding but having removed that I came to an isulation layer of tape the glue on this was pretty strong and much stronger than the inner windings so I could not make out where the 3 wires would attach back to and there was no way of gaining enough length to make new tails. Hopefully some very kind person will contact me and offer thiers of a knackered board. Failing that it's Audi and a fist full of dollars I guess.

Rgds

Mark


----------



## ttsteve

I can't believe (well maybe I can...) that Audi designed a system where the battery is permanently encased and has to be hacked out to change it! User friendly - NOT!


----------



## npfx

Cheers John for that amazing detailed post. I had been meaning to sort this out for years but never got round it.

Had some free time today so I finally went for the plunge. Actually getting it out and sawing it open was easier than I thought. Luckily there was not too much damage from the leaking acid, so a quick cleam with ipa did the trick.

Got the batteries you suggested from Maplin and a new soldering iron and managed to put it all together fairly easily. Worked first time when I plugged it in, but as others have mentioned here, it really is the most patheticly quiet siren I've ever heard.
I'm wondering whether originally it would have been louder, and its corrosion of one of the parts that means its not as loud - or are they all just this crap when new?

Thanks again


----------



## ROADSTA

Thanks John for that,

was unaware what the beebing was, did not occur to me to check it on the forum either, But having just read the write up, gonna have to sort it out.

And Yes the alarm has always had a very low tone, I've owed the car from just over a year old.


----------



## John-H

npfx said:


> Cheers John for that amazing detailed post. I had been meaning to sort this out for years but never got round it.
> 
> Had some free time today so I finally went for the plunge. Actually getting it out and sawing it open was easier than I thought. Luckily there was not too much damage from the leaking acid, so a quick cleam with ipa did the trick.
> 
> Got the batteries you suggested from Maplin and a new soldering iron and managed to put it all together fairly easily. Worked first time when I plugged it in, but as others have mentioned here, it really is the most patheticly quiet siren I've ever heard.
> I'm wondering whether originally it would have been louder, and its corrosion of one of the parts that means its not as loud - or are they all just this crap when new?
> 
> Thanks again


Well done  . It's quite loud if you have it free in your hand. It's squirrelling it away behind all the soft panelling and closing the boot that muffles it. :wink:


----------



## appy1968

for those not so lucky try one of these
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 3D1&_rdc=1

its the replacement part 8L0 951 605A for the now obsolete original Alarm and yes it's the same as that used in the A4 and possibly other Audis

I purchased this and it works fine.


----------



## harrismhome

Not sure if others have discovered this, to remove the alarm I read ealier in this thread and links to other sites describe removing the rear light cluster or trying to remove the 10mm nut which holds the alarm unit in an almost impossible place. Until that is I thought no way do Audi TT get built like this on a production line it just doesn't make sense and it seems I was right. In the picture below there are 2 off 8mm nuts with yellow marker paint these hold a bracket which the alarm is bolted to. Just ease off the rubber seal and pull the inner cover away until you can see the nuts removing these allows you to remove the bracket and alarm as a unit.







[/url]

Rgds

Mark


----------



## Cronas

harrismhome said:


> Not sure if others have discovered this, to remove the alarm I read ealier in this thread and links to other sites describe removing the rear light cluster or trying to remove the 10mm nut which holds the alarm unit in an almost impossible place. Until that is I thought no way do Audi TT get built like this on a production line it just doesn't make sense and it seems I was right. In the picture below there are 2 off 8mm nuts with yellow marker paint these hold a bracket which the alarm is bolted to. Just ease off the rubber seal and pull the inner cover away until you can see the nuts removing these allows you to remove the bracket and alarm as a unit.
> 
> Rgds
> 
> Mark


Thanks for the tip. Slightly different in the coupe. You can't get the carpet out as it is a very stiff cardboard material but you can get your hand in through the flap and feel for the bolts behind the carpet, then get an 8mm spanner on to it. not sure abouit getting it back in yet  but will let you know if i manage it tommorrow


----------



## Cronas

Just tried to do the fix and unfortunatly the board was too badly damaged [smiley=bigcry.gif] I'm gonna have to try and get hold of another one from somewhere? Just out of intrest has anyone managed to attach a different hard wired siren or hard wired the existing one instead of using batteries


----------



## rob1975

if the circuit board is not fried you can take out batteries and throw them away if you want. you just loose battery back-up on siren so if someone cut battery supply alarm would silence. lets be fair if youre more than 10 yards away you probably wouldnt hear it anyway. i replaced my batteries as per the how-to (very informative) but soon after still getting beeps, batteries were charging and were up to about 9.5v wasnt too keen on this so slung them out and lived with the beeps when turning ignition on. it doesnt beep on ignition anymore but alarm still works so that'll do as far as i'm concerned!


----------



## Cronas

Does anyone know if the same siren is used in most of the audi's? A3, A4, A6 etc I have found a couple of breaks that have A4's but no TT's

I also spoke to an alarm company about fitting a 12v siren and they don't think it will work. Because it has a battery backup they believe that it will be sending a digital signal to the siren to check if it is an audi one, aparently this is what the aftermarket alarms do, not sure how true this is. But a battery backup siren would cost around £80 and there is no guarentee it would work.


----------



## appy1968

Cronas said:


> Does anyone know if the same siren is used in most of the audi's? A3, A4, A6 etc I have found a couple of breaks that have A4's but no TT's
> 
> I also spoke to an alarm company about fitting a 12v siren and they don't think it will work. Because it has a battery backup they believe that it will be sending a digital signal to the siren to check if it is an audi one, aparently this is what the aftermarket alarms do, not sure how true this is. But a battery backup siren would cost around £80 and there is no guarentee it would work.


See my post several above

As long as part number is 8L0951605A it will work. This is what audi sell as the replacment for the original part and is used in some other audi's


----------



## horneteer

The alarm in my 2001 keeps going off for no apparent reason. I can stop it by unlocking the car and can hear the siren crackling when its not sounding. Anyone know if this is a symptom of a knackered battery?


----------



## TJS

Switched to the updated alarm unit yesterday ... all pretty straightforward, especially if you take out the rear light unit. Simply enlarged the hole on the mounting bracket (the new siren has the larger bolt) and used a wing nut and shake proof washer to hold the new unit in place.

The problem I now have is two fold.

The end of the plug has turned white and crumbled away exposing half on one of the 3 receptors for the pins on the alarm unit. Suspect I will need anew plug. Are these available and easy to fit or is it a new harness?

Secondly, how do you test if the alarm is working. Sounds a silly question. If I sit in the car with the alarm activated but you cant undo the doors because they are locked. Set the alarm and try to unlock and open the door using the key and the alarm disables.

TJS


----------



## was8v

TJS said:


> Secondly, how do you test if the alarm is working. Sounds a silly question. If I sit in the car with the alarm activated but you cant undo the doors because they are locked. Set the alarm and try to unlock and open the door using the key and the alarm disables.
> 
> TJS


Leave a window open, lock with remote.

Then after a few secs the flashing red door pin lights change speed the alarm is set.

Now wave your hand inside the car!

Or give the car a thump somewhere solid e.g. A pilar.


----------



## TJS

Thanks,

Tested and all working OK . The new unit still isn't very loud but hopefully enough to draw attention.


----------



## JNmercury00

TJS said:


> Thanks,
> 
> Tested and all working OK . The new unit still isn't very loud but hopefully enough to draw attention.


yeah, like a smoker with a cough screaming through a straw! :lol:


----------



## taTTy

So what symptoms peeps getting when the back up batteries give up the ghost.

I have the door lock beep enabled on mine and without warning this stopped ... could just hear a 'click' from the boot when there should have been a bleep.

Thought I'd test the alarm by leaving the window down and waving arm inside ... got a reasonalbe initial 'cheep' but each subsequent one was more and more feeble until it was but a squeek :?

Read previous post that say the alarm starts going off by itself when the batteries start to die but I've not had this. Is it still likley to be these or should I be looking elsewhere

Thanks


----------



## Hoggy

Hi, Once batteries are completely flat & not taking a charge you will hear 3 beeps when turning on ign.If not replaced/repaired fairly quickly, corroding batteries will damage the circuit board & then replacement alarm unit will be required.
Hoggy.


----------



## taTTy

Hoggy said:


> Hi, Once batteries are completely flat & not taking a charge you will hear 3 beeps when turning on ign.If not replaced/repaired fairly quickly, corroding batteries will damage the circuit board & then replacement alarm unit will be required.
> Hoggy.


Cheers Hoggy for the reply .... what stage do you reckon I'm at ... like I say don't get the door lock beep at all, and at no point have I had 3 beeps when turning ignition on. Another job to add to the list ... just need to decide which to now prioritise


----------



## Hoggy

Hi taTTy, Sounds as if batteries are on their way to failing. Remove alarm unit, dismantle & replace batteries as "HowTo" before it corrodes or replace alarm unit.
Hoggy.


----------



## taTTy

Cheers Hoggy ... trip to Maplins it is


----------



## stufearn

What a helpful post! Mine started beeping last week... Followed instructions, bought batteries from Maplins, bobs your uncle... All fixed in under 45 mins and only £12 worse off... Another little fortune saved by being a member of this forum.. Helps to pay for all those expensive things I've bought recently..

Cheers

Stu


----------



## Mondo

Well, yes an excellent How-to. But a bit late for me.  Got the dreaded click-click-click sound earlier this week, so thought, WTF, let's give this a go. Well I managed to get the alarm off through the access panel and hack it open:



But once apart it was toooo late. The PCB contacts are corroded (and the other side of the board too, from what I can see):



And the [email protected] @rsehole cause of the problem - if you discount Audi's penny-pinching design:



Bugger. So now I'm on the look-out for a replacement unit. I'll ring my local stealers on Saturday and get some added incentive to find an alternative source when they tell me the price. Funny guys! :lol: .... not. :x


----------



## John-H

Oh dear  Good pictures though


----------



## Mondo

Cheers John. And thanks to you I at least had the possibility of fixing it, but looks like I'll be dropping my trou' for Epsom Audi before long.  :wink:


----------



## KimTT

my alarm just flashes the indicators..no sound is this broken?


----------



## John-H

Sounds like it unfortunately. Worth taking the lid off to have a look - might not be too bad.


----------



## Mondo

Just FYI. Was at the Stealers this morning, picking up my dipstick/guide, and asked them what the price of the alarm unit was. Just over £90!  Needless to say I'll be trying to source one from somewhere else. :wink:


----------



## johnrolfe

hi 
anyone know if you can use a replacement siren from a vw ,skoda or seat ?


----------



## rachelc

Just a few days ago I bought a 'new' alarm siren from eBay. Statedfor use with VW Golf Mk 5, Golf Mk5, Passat, Bora.

VW Part Number 1K0 951 605C
Audi Part Number: F005V00327

Loom/plug is identical (oblong three-pin) but alas it does not work.

I also checked all fuses and disconnected the car's battery for 2 minutes as I was told this might help.

I bought the unit based on a number of comments on this forum saying these work. OK, there might still be a problem with the car so have kindly asked AVIT (Slough) to check the new siren I have bought.

Only cost £28 so not much of a loss it found to be incompatible.


----------



## Mondo

Hmmm... pretty sure it should work, as it's the same part number for the family. And I'm guessing it was you that won the bid - I stopped at £25. Like you say, worth a punt as the alternative is £90 from a dealer.

The newer-style alarms (rectangular, rather than the old square one) have a 12mm bolt on them (I think) instead of 10mm like on the older one. Not such a problem. But I still need to source one myself from somewhere... :?


----------



## Hoggy

*Mondo wrote*_The newer-style alarms (rectangular, rather than the old square one) have a 12mm bolt on them (I think) instead of 10mm like on the older one. Not such a problem. But I still need to source one myself from somewhere._

Hi, I removed the 10mm bolt from old alarm, filed down the head & used it on new alarm. Easier than trying to drill out bracket on car.
Hoggy.


----------



## Mondo

Damn, that's a good [smiley=idea.gif] Unfortunately I've already thrown my old one out.  Looks like a trip to the Stealer for me.


----------



## John-H

Hoggy said:


> *Mondo wrote*_The newer-style alarms (rectangular, rather than the old square one) have a 12mm bolt on them (I think) instead of 10mm like on the older one. Not such a problem. But I still need to source one myself from somewhere._
> 
> Hi, I removed the 10mm bolt from old alarm, filed down the head & used it on new alarm. Easier than trying to drill out bracket on car.
> Hoggy.


How did you fit the bolt into the new alarm - it's moulded into the plastic isn't it?


----------



## Hoggy

*John-H wrote * _How did you fit the bolt into the new alarm - it's moulded into the plastic isn't it?_

Hi John, The old alarm bolt is molded in..The new alarm 12mm bolt is a tight sliding fit in a recess, I slid that out using screwdriver, got a spare 10mm bolt, filed down the head & slid that into the new alarm recess. 
Hoggy.


----------



## John-H

Hoggy said:


> *John-H wrote * _How did you fit the bolt into the new alarm - it's moulded into the plastic isn't it?_
> 
> Hi John, The old alarm bolt is molded in..The new alarm 12mm bolt is a tight sliding fit in a recess, I slid that out using screwdriver, got a spare 10mm bolt, filed down the head & slid that into the new alarm recess.
> Hoggy.


I see. That sounds like a sound solution - better than drilling out the hole I think


----------



## rachelc

All this talk of bolts etc...

An easier option is to clean the inside and mount the newer style unit using heavy duty sticky velcro.

The new unit tucks right up into the recess nicely.


----------



## blinkinink

Anyone who doesnt fancy converting the batteries from Maplin can try ESP Special Batteries, they will make the batterys with cables attached etc for £8 delivered.......too late for me because the contact on my circuit board were too damaged


----------



## cyberface

if i remove my siren to replace the batteries,. can i use the car without it in? or do i need to do it and get ity back in before using the car?


----------



## Hoggy

Hi cyberface, Yes, you can use TT without the alarm in place.
Hoggy.


----------



## cyberface

well it started badly and ended worse 

hacksaw blade broke straight away, so ended up using a steak knife to cut it open. had to go buy a soldering iron, but without any srt of flux the wires will just not stick to the batteries, managed to get it al back together, and nothing , so looks like itll cost be full wack for a new one, plus £20 i spent rying to get mine working


----------



## cyberface

had another play with it, and as i connect the batteries i can hear the siren 'click' as if its going to work, but when i lock the car no bleep. i went for a good spin, and left it plugged in over night but still nothing, did anyone ever work out if we could get a cheaper vw/skoda alarm to work?


----------



## DiScO

Hi Folks,

Some great info here thanks. My alarm decided to go of at 3.30 this morning for no apparent reason (why always in the early hours of the bloody morning?! :evil: ) Anyway, I have a few questions if you don't mind. The alarm went off but the indicators were not flashing. I find that by locking the car, the alarm goes off every time. At that time of the morning, I took a gamble and just left the car unlocked as it was the only thing I could do and its blocked in my driveway so no big deal. Is there any explanation why the alarm goes off but not the hazzards also? The only thing I can think is I have not driven the car for a few weeks now as I'm waiting to get the cambelt done as it's well overdue. Could it be the alarm batteries are a bit low on charge because of this? I had noticed the 4 beeps coming from the rear at least 4-5 years ago and always wondered what it was. The alarm is sounding ok though. I also checked the doors to make sure the windows dropped and the courtesy lights came on and that seemed fine. I have had a number of electrical problems with this car, including the keyfob refusing to open / unlock the car intermittently. I have replaced the battery in the key and re-programmed it. It works for a bit, but eventually goes intermittent to not working at all until placing it in the lock and manually locking and pressing a few buttons. It a right pain. Just wondering if this could be related as the alarm sometimes only sets when pressing the lock button a few times. I also believe I have the dreaded faulty dash pod (inaccurate fuel gauge etc) and wonder if this could also contribute? To be fair, the alarm has been fine but has only recently started playing up since having not been driven. It would seem the only way I can get the alarm to stop is by starting the engine and then leaving it unlocked! Sorry for the lengthy post, Cheers!


----------



## John-H

The central locking controller triggers the alarm siren and flashes the hazard lights. As your lights have not been flashing then it's likely nothing to do with the triggering of the alarm from the central locking controller, alarm sensors, doors, keys etc. - it's the siren itself acting independently due to acid damage shorting things together within the unit. Part of the Thatcham 1 requirement is that the siren has its own battery and will sound independently of the car's own battery. The triggering of the unit is performed by serial communications from the central locking controller. It could be that the siren is misenterpreting the "arm" message for a "trigger" message - I'm guessing here but I would suggest it's time to take your siren apart and attempt to clean and recondition it or replace it. Disconnecting it will stop the noise at night of course. The fact that you have had the beeps also suggests that the internal battery is in trouble.


----------



## DiScO

John-H said:


> The central locking controller triggers the alarm siren and flashes the hazard lights. As your lights have not been flashing then it's likely nothing to do with the triggering of the alarm from the central locking controller, alarm sensors, doors, keys etc. - it's the siren itself acting independently due to acid damage shorting things together within the unit. Part of the Thatcham 1 requirement is that the siren has its own battery and will sound independently of the car's own battery. The triggering of the unit is performed by serial communications from the central locking controller. It could be that the siren is misenterpreting the "arm" message for a "trigger" message - I'm guessing here but I would suggest it's time to take your siren apart and attempt to clean and recondition it or replace it. Disconnecting it will stop the noise at night of course. The fact that you have had the beeps also suggests that the internal battery is in trouble.


Hi John-H, many thanks for your reply, much appreciated. I took it out and dissected it with a junior hacksaw, came apart nicely actually  Sure enough, one of the cells had literally split open and the board / contacts were covered in acid. I cleaned it up and it looked ok, no apparent damage to the board but when I connected it minus the batteries it just triggered again (it's VERY loud when not concealed behind the boot interior!). I've left it out now and all is well. Information on a spare part seems pretty sketchy from what I can see. Any ideas what my best bet could be? If it's going to be huge money I may just live with it disconnected. I think you are right about the trigger as when I set my alarm without the alarm unit attached and stick my arm through the window, the hazards start flashing. The only silly thing I managed to do was drop the nut when taking it out [smiley=bigcry.gif] If I remove the light cluster do you think I will be able to locate / see it? Or is it lost forever?! Cheers.


----------



## mclaine

Following problem with TT alarm:
1. Unlocking and opening trunk lid from remote key, when doors are locked, will turn on the alarm after a while
2. Sometimes when doors and everything are locked, alarm will turn on by itself

It's 100% sure that nothing is moving inside the car. It's a bit annoying when f.ex you just want to put something in your trunk at middle of parking lot without opening the doors, just unlocking the trunk, you got "loud beeping". And it isn't nice either to have alarm on by itself..
Checked also that those small red led's are stopping flashing when unlocking and opening trunk lid and those will turn back on when closing lid (and trunk lid automatically locks).

Any help would be apprechiated to have alarm working more reliable and I can stop frightening to have unwanted alarm beeps.

Thanks!


----------



## T3RBO

You need to turn the alarm off before opening doors and boot (trunk).


----------



## AudiDoDatDen

T3RBO said:


> You need to turn the alarm off before opening doors and boot (trunk).


I can open boot with alarm on. The indicators flash once when I close the lid, the rest of the car remains locked.


----------



## Shev

k10mbd said:


> my alarm just flashes the indicators..no sound is this broken?


This happens on mine. Can the alarm sound be disabled by vag-com or does this indicate that the alarm siren is broken?


----------



## mclaine

AudiDoDatDen said:


> T3RBO said:
> 
> 
> 
> You need to turn the alarm off before opening doors and boot (trunk).
> 
> 
> 
> I can open boot with alarm on. The indicators flash once when I close the lid, the rest of the car remains locked.
Click to expand...

Exactly what I meant; this was situation in my TT before. Now it's not necessarily working like that anymore. Alarm will start beeping when opening the trunk, not immediately while opening but shortly after it has been open for a while. When closing, the indicators will flash and the rest of doors remains locked.

So I'm wondering what is wrong because it is not working anymore like that.. And it is random behaviour, not always. Weard.


----------



## robbyvanz

John,

Do you think a new VW siren can be used as a replacement? It is about half the cost of the Audi unit. The only difference I see is the ground and signal wires are reversed. Just wondering if anyone on here has tried it.

http://www.audizine.com/forum/showthrea ... g-VW-Alarm

Thanks, 
Robby


----------



## John-H

It looks quite likely but I can't be sure without trying it.


----------



## robbyvanz

John,

Can you confirm the Audi Siren sounds the same as this VW one in this video:






My old Audi siren used to just beep constantly when the alarm was activated. The one in the video sounds more like a siren. The locking sound is the same.

Thanks, 
Robby


----------



## John-H

As you say the VW alarm in that video is different with modulated alarm tone. The standard Audi tone is an on-off beep.


----------



## mm1946

After hearing about possible problems with alarm was going to remove and replace batteries, if I can get any. But if anyone has any info on VW alarm migh be better to go down this route.


----------



## potsie

Hi All,

Just bumping this up regarding the VW siren..... my current siren is in half, batteries corroded, circuit unit looking a little worse for wear..... not sure I personally would be able to attempt the fix and if it would work..... I haven't looked into obtaining a new unit from audi yet... trying to put it off if there is a cheaper fix!

cheers


----------



## shauny3779

Fantatastic post! Pulled mine apart today as it kept going off!!


----------



## Adam-tt

i used this how to today thanks for posting it up


----------



## sazismail

Excellent write up.. just went to check why my alarm aint working.. and i just found out there is no alarm there!!!!! just the cable hanging for it, well i guess i wont be repairing then but buying, lol


----------



## Sickboy

sazismail said:


> Excellent write up.. just went to check why my alarm aint working.. and i just found out there is no alarm there!!!!! just the cable hanging for it, well i guess i wont be repairing then but buying, lol


My fix didn't work because it was shot. Never bothered replacing it, about as loud as a fart in a bucket anyway! :?


----------



## John Stratton

Brilliant Write Up . Thanks John . All users owe you a drink !!!!

My alarm was working but thought now is the time to check its batteries . Whilst in the garage for winter .

I found one battery slightly leaking with small acid deposits visible , luckily the damage looks minimal so think I have caught it in time thanks to this post . Batteries did read 3.9 and 4.1 volts on my voltage tester so still alive .

Ordered the batteries from RS components today , £13.76 including postage . Saves a trip into town to Maplin but think there's are about the same total cost anyhow. Thanks Hoggy for the link .

I did remove the rear light cluster to gain better access to the single 10mm nut .

Soldering iron ready to complete the task .

Once again John H , Many Thanks .

John


----------



## Taylortony

Just done mine today, had problems with the batteries from RS not accepting solder, but they are investigating them, might have been a bad batch, Maplins ones are fine which I used instead.... Mine had the odd beep and when opened a battery had started to weep and had corroded one of the battery terminals on the board...... One thing I took the alarm out and the damn thing went off in my hand, I nearly poo'd myself.. 

I took the rear light out as it takes seconds to do.


----------



## staff65

Hi 
Thanks all for this thread. A sleepless start to last night had me up disconnecting the battery at midnight. But i now now the cause and cure!

So, today, i have located the unit, unscrewed the nut and unclipped the cable.
I have not yet had the unit open but did notice stone severe damage and corrosion to the end of the cable?? Can the head of this be sourced/replaced??

Last week i had the2 occasions of a flat battery and this week had to replace. Recently i haven't been using it much, coukf the siren issue have caused the battery problem?

Currently the siren box is off. Is it ok lleft off in the short term until i have time to fix it?
Will the alarm still work at all?

Thanks in advance for any advice!


----------



## Hoggy

Hi Staff65, Corroded siren has been known to flatten main battery. Indicators will still flash if "alarmed" even if siren is disconnected, & will not cause any probs.
Hoggy.


----------



## jnwright71

Hi Guys,

If you cannot repair, source a replacement from ebay Germany (http://www.ebay.de). I bought a new one and including delivery it was only circa £30. You will need to drill out the bracket as the bolt on the new unit (superceded design) is bigger than the original, but takes mere minutes. I suggest removing the rear light cluster as it takes aless than a minute and access makes it much easier.

Watch out for corrosion in the plug connect to the wiring loom. I had this and had to replace the plug. To find out more, see my post this : viewtopic.php?f=2&t=297481

Enjoy, James.


----------



## qreidford

Hi

I finally got around to dealing with my battery issue in the alarm sounder box - just in time as one battery had done a pretty good job of growing fur on the -ve terminal and one of the three pins on the plug to the loom was black!! 
Thank goodness for this forum and John H - faultless instructions although getting into the case was traumatic as was cutting out the old battery housing. Thanks also to WAK or I would never have realised that the rear light cover was held by a ball socket joint!

All I need to do is fugure out how to get the 'beep on lock' option to work using my free version of the VagCom software - does that do the job?

Thanks to all who contributed to this fix


----------



## jackliew

Just want to know any one here get a deferent model siren fix in found out in market got so many model but it just two wire only red and black but audi one got 3 pls help and no luck replace the batt coast me more than 20 help pls


----------



## John-H

jackliew said:


> Just want to know any one here get a deferent model siren fix in found out in market got so many model but it just two wire only red and black but audi one got 3 pls help and no luck replace the batt coast me more than 20 help pls


If I'm reading you correctly it sounds like you have bought a 12V DC siren. This won't work. The Audi siren is controlled by a digital signal - hence the three wires +\- power and signal. You need the correct Audi siren.


----------



## Roncella

Very helpful, many thanks


----------



## ttsteve

I tried to fix mine a couple of years ago - see post earlier in this thread. Basically I had left it too long and the unit had been battery acid damaged etc. So I ended up fitting a new one. I did make up a new battery pack as described and I still have that, though I discarded the alarm itself.


----------



## sallyday10

jackliew said:


> Just want to know any one here get a deferent model siren fix in found out in market got so many model but it just two wire only red and black but audi one got 3 pls help and no luck replace the batt coast me more than 20 help pls


Once more in English please?


----------



## Peeunit

This is exactly what I needed. Amazing. Thanks


----------



## kevin_tt

Great Post
I got the beeping when I turned on the ignition a couple of times so decided to go for battery replacement.
Bought batteries from RS. Stock No. 525-792
The circuit board had a lot of fur on it but it all cleaned up with a dowsing of WD40
The old batteries were 170mAh but only showed 2 volts on one and 0.8 volts the other.


----------



## martyk

only had my TT a few weeks and no problems with the siren as yet, but a year ago i had a very sleepless nite when my B7 S4 was beeping on the driveway. it even beeped when i drove it away at 4am, for fear of waking the neighbours.

anyway i found that this siren problem has been here since the mid 90's on the B5 Audi A4's. in fairness this TT was released during the same period.

with my B7 S4 i ended up disconnecting the siren from the printed circuit board via the tiny 2 wire plug. left it like that.

at least i know where this siren is if it goes bad.


----------



## jd2008

Does anyone know if these batteries would work?

http://www.amazon.co.uk/Ni-MH-backup-ba ... B004QNSJFK


----------



## John-H

jd2008 said:


> Does anyone know if these batteries would work?
> 
> http://www.amazon.co.uk/Ni-MH-backup-ba ... B004QNSJFK


They are the same electrical spec as the ones I detailed only they are not the flattened shape but circular, so will sit higher when lying down. You therefore might have a space problem. Best compare the two dimensionally - perhaps the stood up height is a better orientation.


----------



## jd2008

Cheers John,

I thought the specs looked ok and because they were rounded they might fit straight in.

Great post btw


----------



## Evil_FaTT_Homer

John-H said:


> They are the same electrical spec as the ones I detailed only they are not the flattened shape but circular, so will sit higher when lying down. You therefore might have a space problem. Best compare the two dimensionally - perhaps the stood up height is a better orientation.





jd2008 said:


> I thought the specs looked ok and because they were rounded they might fit straight in.


Hi Just noticed this was posted recently - did you try the fix with these batteries ?

Thanks, 
EFH


----------



## markymark1

I've just taken the siren out of my car tonight as I'm having trouble with the battery draining and I'm told this is a result of the batteries dying, so I'm going to try this fix and hope it's successful, I'll let you know how I get on 

Great 'how to' by the way John, well done [smiley=cheers.gif]

Mark


----------



## markymark1

Just a thought, would it be more practical to bring the wires through the casing and have the batteries mounted on the outside for future replacement :?: [smiley=gossip.gif]


----------



## Saint TT

Hi
Just a quick question regarding the charging of the batteries. 
I did the fix with the Maplin batteries this weekend after hearing the tell tale bleeps last week. 
The batteries were part charged enough to set off the alarm when triggered but still after a few days I get the bleeps on my morning start up. 
Do these batteries only charge when driving and if so how long does it take to get them up to spec. 
Beginning to think I've been sold done duds.

Thanks

Saint


----------



## jhoneyman

Saint TT said:


> Hi
> Just a quick question regarding the charging of the batteries.
> I did the fix with the Maplin batteries this weekend after hearing the tell tale bleeps last week.
> The batteries were part charged enough to set off the alarm when triggered but still after a few days I get the bleeps on my morning start up.
> Do these batteries only charge when driving and if so how long does it take to get them up to spec.
> Beginning to think I've been sold done duds.
> 
> Thanks
> 
> Saint


I am glad you asked this as I too have the bleeps, Not everyday but some days when I start her in the morning.
Actually when I run a VAGCOM scan the alarm shows some faults. 
The alarm works, but these bleeps do happen.


----------



## daztheblue1976

just had a go at this fix thanks john 8 year old thread wow  , think my board was beyond repair though so off to ebay


----------



## markymark1

Just be careful then if your buying a used one off ebay  I've been looking for a while now and I expect that the majority of sirens on there are old and in the same condition as yours, it's impossible to tell without stripping them unless you plug them in and try them :!: you can return them sometimes but then you have to start looking again :!: 
I bought one off ebay as I'de done exactly the same as you, mine was destroyed by acid inside (worse than your pic) the circuit lines had been eaten away, the car was in bits as I had the dash out and no battery so I couldn't test the new one. It had a warranty, but I took pot luck and cut it apart and found the replacement was just as bad and beyond repair  
I've been looking for a few weeks now and would love to know if there's another siren which would do the job say from a newer TT or one of the A's, I'll ask the question.
I hope you have better luck than me, let us know how you get on [smiley=gossip.gif]

All the best, Mark


----------



## warrenstuart

I'm just in the middle of doing the siren fix on my daughters car and that board of yours should clean up, i've saved hers with a fine stiff brush and some solvent cleaner.
It was like this when i opened it up...










The plug had rotted and just fell apart too so i've got the parts from local VW dealer to replace that today










Have a go at cleaning it up and save your cash :wink:

Warren.


----------



## markymark1

warrenstuart said:


> I'm just in the middle of doing the siren fix on my daughters car and that board of yours should clean up, i've saved hers with a fine stiff brush and some solvent cleaner.
> It was like this when i opened it up...
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The plug had rotted and just fell apart too so i've got the parts from local VW dealer to replace that today
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Have a go at cleaning it up and save your cash :wink:
> 
> Warren.


Agreed, your board looks quite good, you might be lucky  
As warrenstuart says give it a good clean up as stated.
I wish mine had looked like this one lol


----------



## daztheblue1976

ive managed to get one from ebay for £35 and i know its a bit of pot luck really, im hoping i will be able to replace the unit if it is infact knackered

and the tracks look to have been eaten away on my board the pics i had taken were after i tried to clean off the muck

just checked the listing and he does accept returns so if all else fails, its the newer version of alarm too so fingers crossed


----------



## markymark1

daztheblue1976 said:


> ive managed to get one from ebay for £35 and i know its a bit of pot luck really, im hoping i will be able to replace the unit if it is infact knackered
> 
> and the tracks look to have been eaten away on my board the pics i had taken were after i tried to clean off the muck
> 
> just checked the listing and he does accept returns so if all else fails, its the newer version of alarm too so fingers crossed


Let us know how you get on and if the newer version looks any better inside or if it's prone to the same problems.

I hope this works for you


----------



## daztheblue1976

Will do but if it doesn't work I will be sending it back to the seller for a refund, and maybe asking audi for one from there recycle bin as mentioned before ha


----------



## warrenstuart

Well despite my earlier post the alarm siren on my daughters car is dead [smiley=bigcry.gif] 
Several hours of fault finding and testing at the weekend didn't bring it back to life and even though everything meters ok the car just doesn't see it when connected... alarm LEDs in door cards take 10 seconds or so before they start to flash after locking the car instead of intantly.

Alarm PCB under magnifier quite clean apart from some lacquer taken off a couple of tracks that are intact and meter out ok










The battery acid had also eaten away at the connector on the car as shown in earlier post so i had to get a replacement from the local VW dealer.
Fabric tape wound back, old corroded plug cut off with wires staggered and new one soldered on with heat shrink to cover the joints.










After testing with the working siren from our car the fabric tape was wound back around the joint to insulate and tidy it up.

The part number on the corroded plug has now changed so you need to order 3D0 973 703 if you need one, £4.28.
This is just the plug housing so you will need the wires and pins too, they come pre assembled as a short length with pins on each end so that you cut them in half so that one end fits into the plug housing and the cut end is free ready to make a joint. Part number per wire set (one wire with a pin on each end so cut in half to make two) 000 979 019 E, £3.90 ea.

If anyone has a spare working siren i need one, also if anyone needs the batteries from Maplin to replace theirs i have a set pre assembled surplus to requirement shown in pic below. **now sold**










Warren.


----------



## daztheblue1976

Sorry to hear things didn't go to plan warren, but thanks so much for the heads up on the new coding for the connectors and wires mine has been eaten away too so need to get that before I can fully test the second hand alarm I picked up from eBay!

Also pm.d you about your batteries will take them incase I can get my old alarm working cheers


----------



## John-H

That's a shame Warren


----------



## jhoneyman

I also bought a 2nd hand one from Ebay and also done this fix.
Unfortunately it didn't work either (PCB was slightly damaged) ... I will probably buy a very expensive new one.


----------



## warrenstuart

John-H said:


> That's a shame Warren


I know, it wasn't for the want of trying as i've worked electronics and did component level repair for a number of years but i couldn't get this going, just no comms with the car :?

Never mind, you win some, you lose some!

I think a good preventative maintainence check here for eveybody with cars 8 years or older is to unplug the alarm siren and see if the connector on the car loom is clean or if it is starting to show signs of battery acid contamination before too much damage gets done. I suspect at this point the siren may still be working.

Warren.


----------



## stupott111

hey i done my siren just as said on here , when i plugged it in , i set off the alarm all i could hear was quiet beeps , thats it , i have waited a few days now , still the same , is there any kind if siren upgrade ? 
or anyone have one they wan a sale cheap ? lol


----------



## stupott111

hey i tried to do mine but all i got was beeps 3 days on still same ?
any ideals ?


----------



## Hoggy

stupott111 said:


> hey i tried to do mine but all i got was beeps 3 days on still same ?
> any ideals ?


Hi, Siren batteries not charging for some reason. Check connection plug/pins again for corrosion. 
Hoggy.


----------



## John-H

Unfortunately if it doesn't work after replacing the battery and the connector is Ok, the chances are that there is some component or PCB damage that you've not seen. Some of the tracks run under components and could be eaten away there, so you'd have to remove the component to see it. The metallisation on the component terminals themselves can also be eaten through, in which case you need to replace the component too. I repaired one once involving several component changes and soldering down thin wire to replace tracks. It's not really economical when it gets like that so it pays to catch it early.


----------



## markymark1

Does anyone have a wiring diagram of the mk1 alarm system, I'de love to be able to work out how to wire in a siren/horn using the alarm indicator feed, but the feed would have to be picked up only when the alarm is triggered and not when the indicators or hazards are used.....this must be possible, as the siren (if you have one that's working) doesn't sound when you use your indicators, any thoughts ?
I've tried the fix and like others the PCB was beyond repair, bought another which was just as bad so not much hope unless you buy a new one, or maybe there is a way around this problem.


----------



## John-H

It's a digital serial communication signal that triggers the alarm. You need something to listen in on the bus for its address and command data and respond to it. The easiest way to trigger a bigger siren is to use a working alarm module to do the translation from the bus and act as relay. You can't simply "wire in" a conventional siren.


----------



## markymark1

John-H said:


> It's a digital serial communication signal that triggers the alarm. You need something to listen in on the bus for its address and command data and respond to it. The easiest way to trigger a bigger siren is to use a working alarm module to do the translation from the bus and act as relay. You can't simply "wire in" a conventional siren.


But could you pick up the power feed from the indicators when the alarm is triggered to operate the horn without it sounding all the time when the indicators or hazards are operated normally, is this what you are saying above in technical terms John?
Always willing to learn and gain knowledge [smiley=book2.gif]


----------



## daztheblue1976

Well the one I bought off eBay was worse then the one I took off my car! Fortunately the seller gave me a full refund so today managed to pick up the slightly newer version from German eBay for £25 so hoping this one works now, as I have emailed audi and they wanted £120 for a new siren


----------



## John-H

markymark1 said:


> John-H said:
> 
> 
> 
> It's a digital serial communication signal that triggers the alarm. You need something to listen in on the bus for its address and command data and respond to it. The easiest way to trigger a bigger siren is to use a working alarm module to do the translation from the bus and act as relay. You can't simply "wire in" a conventional siren.
> 
> 
> 
> But could you pick up the power feed from the indicators when the alarm is triggered to operate the horn without it sounding all the time when the indicators or hazards are operated normally, is this what you are saying above in technical terms John?
> Always willing to learn and gain knowledge [smiley=book2.gif]
Click to expand...

As far as I know it's the central locking controller that sends out the signal down the bus to trigger the siren and at the same time triggers the hazard relay to start flashing. If that is done by a simple level triggered control line then yes you could trigger a siren directly with that but it would also trigger when the hazards triggered for locking/unlocking the car. I suppose you could add a timer to ignore momentary flashes but that's getting complicated. If it's a serial com's line you'd be back to the same problem. I'llhave to check the wiring diagram to see if the serial K line goes to the hazard switch.


----------



## blythe92

I have a similar problem in that my old alarm was dead so bought a new one from Audi, went to fit it but when i plug it in the siren goes off straight away, i presume its the connector as well? is this a relatively easy fix?

Cheers


----------



## John-H

Try cleaning it first. You may have to replace it - requires crimp tools and the right parts of course.


----------



## markymark1

John-H said:


> markymark1 said:
> 
> 
> 
> 
> 
> John-H said:
> 
> 
> 
> It's a digital serial communication signal that triggers the alarm. You need something to listen in on the bus for its address and command data and respond to it. The easiest way to trigger a bigger siren is to use a working alarm module to do the translation from the bus and act as relay. You can't simply "wire in" a conventional siren.
> 
> 
> 
> But could you pick up the power feed from the indicators when the alarm is triggered to operate the horn without it sounding all the time when the indicators or hazards are operated normally, is this what you are saying above in technical terms John?
> Always willing to learn and gain knowledge [smiley=book2.gif]
> 
> Click to expand...
> 
> As far as I know it's the central locking controller that sends out the signal down the bus to trigger the siren and at the same time triggers the hazard relay to start flashing. If that is done by a simple level triggered control line then yes you could trigger a siren directly with that but it would also trigger when the hazards triggered for locking/unlocking the car. I suppose you could add a timer to ignore momentary flashes but that's getting complicated. If it's a serial com's line you'd be back to the same problem. I'llhave to check the wiring diagram to see if the serial K line goes to the hazard switch.
Click to expand...

Thanks for that John, it sounds a little more complicated than I first thought...if only life could be that simple :mrgreen: 
I think I might have to stump up for a new siren eventually, however, it's not essential because the alarm still works and as far as I understand the sirens not worth a wet wipe according to those who's work :-? 
Keep up the good work John the how to threads are very helpful.

[smiley=cheers.gif]


----------



## jd2008

My siren was beyond repair, I've got 2x unused 3.6v 160mah Maplin batteries for sale

Were £8 each, both for £10 + 1.50 postage.

PM me if you're interested.

Cheers,


----------



## blythe92

I've given up on fixing my alarm, bought a new alarm from Audi, replaced wiring and connector but still goes off as soon as I plug it in. Oh well I find they take no notice of alarms now anyway.

Sent from my Nexus 5 using Tapatalk


----------



## John-H

Sounds like you have a problem with the central locking controller sending out a false trigger signal to make it go off. Did you try locking and unlocking the car with the fob whilst the siren was sounding?


----------



## warrenstuart

blythe92 said:


> I've given up on fixing my alarm, bought a new alarm from Audi, replaced wiring and connector but still goes off as soon as I plug it in. Oh well I find they take no notice of alarms now anyway.





John-H said:


> Sounds like you have a problem with the central locking controller sending out a false trigger signal to make it go off. Did you try locking and unlocking the car with the fob whilst the siren was sounding?


Replaced daughters alarm siren yesterday with the newer style "suffix A" siren (8L0951605A) that Audi now sell as a replacement for the old obsolete unit.










Audi say that you also need an additional bracket that they sell for £6 to make it fit but the siren i purchased from a forum member on here just bolted straight on in place of the old one.

Regarding the above comments it did go off as soon as i plugged it in but i just locked/un-locked the car to re-set it, did a couple of test activations and it works fine 

Warren.


----------



## John-H

Is it any louder Warren out of interest or as I expect just the same?


----------



## warrenstuart

John-H said:


> Is it any louder Warren out of interest or as I expect just the same?


I think it's louder, the original one was never gonna be anything to write home about though was it!

Warren.


----------



## John-H

It would be difficult to be quieter :wink:


----------



## Fizzleh

I fitted one of the updated alarms to my car last night but I didn't get the alarm going off.

The battery in the replacement alarm might be dead. Does it charge whilst driving the car or regardless if the car is running or not.

Also how do I set the alarm off? I've tried everything to set the alarm off to no joy [smiley=bigcry.gif]


----------



## warrenstuart

Fizzleh said:


> I fitted one of the updated alarms to my car last night but I didn't get the alarm going off.
> 
> The battery in the replacement alarm might be dead. Does it charge whilst driving the car or regardless if the car is running or not.
> 
> Also how do I set the alarm off? I've tried everything to set the alarm off to no joy [smiley=bigcry.gif]


Does the red LED in the top of the door card start to flash as soon as you lock the car or is there a delay of a few seconds?
If there is a delay then the car isn't communicating with the alarm siren you've fitted.

To set the alarm off i locked the car with the drivers door window down, waited for the red LED in the door card to start to flash slowly (20 seconds-ish) then just waved my arm around inside the car through the open window and it went off almost instantly.

Warren.


----------



## Fizzleh

warrenstuart said:


> Fizzleh said:
> 
> 
> 
> I fitted one of the updated alarms to my car last night but I didn't get the alarm going off.
> 
> The battery in the replacement alarm might be dead. Does it charge whilst driving the car or regardless if the car is running or not.
> 
> Also how do I set the alarm off? I've tried everything to set the alarm off to no joy [smiley=bigcry.gif]
> 
> 
> 
> Does the red LED in the top of the door card start to flash as soon as you lock the car or is there a delay of a few seconds?
> If there is a delay then the car isn't communicating with the alarm siren you've fitted.
> 
> To set the alarm off i locked the car with the drivers door window down, waited for the red LED in the door card to start to flash slowly (20 seconds-ish) then just waved my arm around inside the car through the open window and it went off almost instantly.
> 
> Warren.
Click to expand...

there's a delay of about 11 seconds, I guess the replacement alarm siren I've bought is a dud then?


----------



## warrenstuart

Fizzleh said:


> there's a delay of about 11 seconds, I guess the replacement alarm siren I've bought is a dud then?


Yes i would say it is 

Warren.


----------



## Fizzleh

warrenstuart said:


> Fizzleh said:
> 
> 
> 
> there's a delay of about 11 seconds, I guess the replacement alarm siren I've bought is a dud then?
> 
> 
> 
> Yes i would say it is
> 
> Warren.
Click to expand...

Replaced it with a 2nd alarm siren and now I can confirm the issue is somewhere else.

could this connector be the problem? one end looks as if it could be corroded. How would I test the current to this connector? with a circuit tester?


upload pictures free


----------



## Hoggy

Hi, Corrosion does creep into plug/loom if left too long & 1 socket does look corroded.
Digital Multimeter set to 20 V DC & insert probes into sockets & see if you get any volts.
Hoggy.


----------



## warrenstuart

Fizzleh said:


> warrenstuart said:
> 
> 
> 
> 
> 
> Fizzleh said:
> 
> 
> 
> there's a delay of about 11 seconds, I guess the replacement alarm siren I've bought is a dud then?
> 
> 
> 
> Yes i would say it is
> 
> Warren.
> 
> Click to expand...
> 
> Replaced it with a 2nd alarm siren and now I can confirm the issue is somewhere else.
> 
> could this connector be the problem? one end looks as if it could be corroded. How would I test the current to this connector? with a circuit tester?
> 
> 
> upload pictures free
Click to expand...

The top pin looks like it may be ok, middle pin questionable and bottom pin totally black so even using a multi-meter you may get false readings as it may seem ok off load (not connected) but with the corrosion most likely wouldn't power the siren module when plugged in.
If i were you i'd get a replacement connector and pins from local VW/Audi dealer, chop the old one off (noting what wires go to what pins first) and fit a new one as i did on my daughters car in the copy of my post from page 16 shown below: -

The battery acid had also eaten away at the connector on the car as shown in earlier post so i had to get a replacement from the local VW dealer.
Fabric tape wound back, old corroded plug cut off with wires staggered and new one soldered on with heat shrink to cover the joints.










After testing with the working siren from our car the fabric tape was wound back around the joint to insulate and tidy it up.
The part number on the corroded plug has now changed so you need to order 3D0 973 703 if you need one, £4.28.
This is just the plug housing so you will need the wires and pins too, they come pre assembled as a short length with pins on each end so that you cut them in half so that one end fits into the plug housing and the cut end is free ready to make a joint. Part number per wire set (one wire with a pin on each end so cut in half to make two) 000 979 019 E, £3.90 ea.

Good luck.

Warren.


----------



## Fizzleh

thanks for the help hoggy and Warren. I think I maybe lucky, the alarm I picked off on eBay had an old clip attached to it but the wires leading into it are only a couple cm in length. I'll have to be extremely careful to reattach it, or else it's a new clip.


----------



## dcrutt

thanks john-H for the great write up i fixed my alarm as per instructions and it works fine now
many thanks 
dave


----------



## John-H

Good to hear


----------



## aavuss

I have the usual beeping siren, leaking batteries, dirty pcb issue on my 2003. Am I right in thinking I can test the siren, once the pcb is clean, by reconnecting to the car without any back up batteries? I don't really want to fit new batteries if the pcb is expired!!
Cheers.


----------



## Hoggy

aavuss said:


> I have the usual beeping siren, leaking batteries, dirty pcb issue on my 2003. Am I right in thinking I can test the siren, once the pcb is clean, by reconnecting to the car without any back up batteries? I don't really want to fit new batteries if the pcb is expired!!
> Cheers.


Hi, If PCB has expired internal or main battery will make no difference. 
Remove & open it up & clean circuit board asap, may be the only way to save it.
Hoggy.


----------



## aavuss

Hi
The siren was randomly sounding. I have now removed the siren, and opened it. One of the internal batteries is leaking, and it has leaked onto the siren pcb.
What I wanted to know is, once I have cleaned up the pcb and removed the old siren batteries, can I test the siren on the car before fitting the replacement siren batteries, so as to avoid fitting new batteries to a possibly expired pcb?
Apologies for not making myself clear - I hope I have now!  
Cheers


----------



## Sandy

Can the siren horn be replaced whilst box is open for a louder horn or has anyone tried to replace it?. Edited again lol
I guess no one's interested


----------



## Hoggy

Hi, Difficult to say, as the charging circuit may be part of the system.Try it is the only way to find out.
Having the alarm "open" should cause any probs, that's the way I would test it. 
Hoggy.


----------



## John-H

I don't think so. The battery is trickle charged to accumulate enough energy to make an alarm sound. Without the battery in place there would be no reservoir and stabilisation of voltage. The supply would likely collapse the first time the alarm was triggered and if the battery is used for regulation the trickle charger could cause excessively high voltage and possibly damage the ICs - it depends on how it's been designed and I don't know for sure.

You could always get an alternative NiCd battery of the same voltage and temporarily connect that to test it on the system.


----------



## aavuss

Ok thanks - will just have to test with the batteries then! 
If anyone bought the batteries, but their siren pcb was shot, I will be interested in purchasing..


----------



## John-H

You don't need to buy the NiCd batteries to test it but could test it with any other battery of the right approximate voltage.










You could use five x 1.5V AA cells (7.5V) and even four might work. Don't goo too much higher though.


----------



## Boruki

If you (or anyone) wants the two batteries drop me a pm as I have a pair. My battery had more acid burn than clean plastic..


----------



## Mr_Smith

Boruki said:


> If you (or anyone) wants the two batteries drop me a pm as I have a pair. My battery had more acid burn than clean plastic..


Hi Boruki,

I can't PM but I'd appreciate the batteries as mine started doing this on Sunday!

All,

Is it okay to disconnect the siren until I get this sorted?


----------



## merlin c

Mr_Smith said:


> Boruki said:
> 
> 
> 
> If you (or anyone) wants the two batteries drop me a pm as I have a pair. My battery had more acid burn than clean plastic..
> 
> 
> 
> Hi Boruki,
> 
> I can't PM but I'd appreciate the batteries as mine started doing this on Sunday!
> 
> All,
> 
> Is it okay to disconnect the siren until I get this sorted?
Click to expand...

Get it out now and cut it open or the battery damage to the pcb may be too much!!!


----------



## EnthusiastOwned

Hi All,

My original siren is fried. I tried the new batteries from Maplins but the PCB is fried. I've bought a replacemen. Plugged it in and nothing, it doesn't work? Am I right in thinking the batteries could just be flat and it needs a charge for 24 hours or should I start looking at other things?

Rich


----------



## Mr_Smith

merlin c said:


> Mr_Smith said:
> 
> 
> 
> 
> 
> Boruki said:
> 
> 
> 
> If you (or anyone) wants the two batteries drop me a pm as I have a pair. My battery had more acid burn than clean plastic..
> 
> 
> 
> Hi Boruki,
> 
> I can't PM but I'd appreciate the batteries as mine started doing this on Sunday!
> 
> All,
> 
> Is it okay to disconnect the siren until I get this sorted?
> 
> Click to expand...
> 
> Get it out now and cut it open or the battery damage to the pcb may be too much!!!
Click to expand...

Hey, thanks for the heads up. I didn't realise the batteries would corrode so quickly, it has been about 24hrs since it started. How often do these need changing? It's a 2006 so is it likely this is the first time the batteries have died?


----------



## merlin c

EnthusiastOwned said:


> Hi All,
> 
> My original siren is fried. I tried the new batteries from Maplins but the PCB is fried. I've found a replacement (from a 2014 A1 which is being broken local). Plugged it in and nothing, it doesn't work? Am I right in thinking the batteries could just be flat and it needs a charge for 24 hours or should I start looking at other things?
> 
> Rich


Is this the part number you have on it Rich 8L0 951 605A??? If so try locking and unlocking the car, that normally resets the alarm.


----------



## EnthusiastOwned

merlin c said:


> EnthusiastOwned said:
> 
> 
> 
> Hi All,
> 
> My original siren is fried. I tried the new batteries from Maplins but the PCB is fried. I've found a replacement (from a 2014 A1 which is being broken local). Plugged it in and nothing, it doesn't work? Am I right in thinking the batteries could just be flat and it needs a charge for 24 hours or should I start looking at other things?
> 
> Rich
> 
> 
> 
> Is this the part number you have on it Rich 8L0 951 605A??? If so try locking and unlocking the car, that normally resets the alarm.
Click to expand...

Damn, I have: 1K0951605C

Looks identical. I should have checked the numbers. :lol:


----------



## Boruki

I'll drop you a pm about the batteries


----------



## merlin c

EnthusiastOwned said:
 

> merlin c said:
> 
> 
> 
> 
> 
> EnthusiastOwned said:
> 
> 
> 
> Hi All,
> 
> My original siren is fried. I tried the new batteries from Maplins but the PCB is fried. I've found a replacement (from a 2014 A1 which is being broken local). Plugged it in and nothing, it doesn't work? Am I right in thinking the batteries could just be flat and it needs a charge for 24 hours or should I start looking at other things?
> 
> Rich
> 
> 
> 
> Is this the part number you have on it Rich 8L0 951 605A??? If so try locking and unlocking the car, that normally resets the alarm.
> 
> Click to expand...
> 
> Damn, I have: 1K0951605C
> 
> Looks identical. I should have checked the numbers. :lol:
Click to expand...

As you now know that does not work, here is the one I bought, get one with the plug on and enough cable(2 inches) to splice it on, the newer plugs contacts should be in very good condition. 


*Here ya go*...http://www.ebay.co.uk/sch/i.html?_trksi ... &_from=R40


----------



## sheepshearer

fix for the newer (10 years old) unit is much the same. case opens with a sharp knife.










2004 TT 3.2l NA


----------



## EnthusiastOwned

merlin c said:


> As you now know that does not work, here is the one I bought, get one with the plug on and enough cable(2 inches) to splice it on, the newer plugs contacts should be in very good condition.
> 
> *Here ya go*...http://www.ebay.co.uk/sch/i.html?_trksi ... &_from=R40


I'm reluctant to buy a used one for fear of it also being beyond repair. I'm just going to suck it up and buy a new one.

I think my old one is fried as the car was dry stored for two years so it screwed the back up batteries in the process. Lower mileage isn't always better in some cases. :lol:


----------



## eldiablott

sorry for bumping but im just wondering, when unlocking or locking the car via the remote is the car supposed to beep at all? im just asking because mine doesnt. lights flash and all the usual stuff though


----------



## Hoggy

Hi, No beep as standard, but can be enabled via VagCom/VCDS.
Hoggy.


----------



## eldiablott

Hoggy said:


> Hi, No beep as standard, but can be enabled via VagCom/VCDS.
> Hoggy.


oooh didnt know that. im like a bairn and love my cars to beep haha.
is there an easy way to test the alarm works, (without bricking a window) :lol:


----------



## warrenstuart

eldiablott said:


> Hoggy said:
> 
> 
> 
> Hi, No beep as standard, but can be enabled via VagCom/VCDS.
> Hoggy.
> 
> 
> 
> oooh didnt know that. im like a bairn and love my cars to beep haha.
> is there an easy way to test the alarm works, (without bricking a window) :lol:
Click to expand...

Lock it with the drivers window down them wave your arm inside the car after a min or so.

Warren.


----------



## eldiablott

warrenstuart said:


> eldiablott said:
> 
> 
> 
> 
> 
> Hoggy said:
> 
> 
> 
> Hi, No beep as standard, but can be enabled via VagCom/VCDS.
> Hoggy.
> 
> 
> 
> oooh didnt know that. im like a bairn and love my cars to beep haha.
> is there an easy way to test the alarm works, (without bricking a window) :lol:
> 
> Click to expand...
> 
> Lock it with the drivers window down them wave your arm inside the car after a min or so.
> 
> Warren.
Click to expand...

spot on, cheers


----------



## tommatt90

Do these look fine instead of maplins ones?

http://m.rs-online.com/h5/mobile/uk/cat ... 0525792%2F


----------



## Hoggy

tommatt90 said:


> Do these look fine instead of maplins ones?
> 
> http://m.rs-online.com/h5/mobile/uk/cat ... 0525792%2F


Hi, yes, they are O.K. can sometimes be cheaper from RS, but not always in stock.
Hoggy.


----------



## DrJohnSmithUNIT

A good way to test the alarm without leaving the window down: Leave a kitten in a travelling cage in the car when you lock it up , triggers it well


----------



## sussexbythesea

Another alarm brought back from the brink using this 'How-to'...thanks.

I fitted the Maplin batteries recently as the board did not seem to show signs of major damage but it appeared to be dead so gave up and started looking at replacements :roll:

Thought I'd give it one more go today and noticed a faint clicking when I plugged it in so spent a bit more time cleaning the connector and testing (arm through the open window jobbie :!: )........and it's working, well it loud enough for me in the garage with the door closed 

Happy with that


----------



## John-H

Success!


----------



## jhoneyman

Hi all,
Does anyone know if this would be a good substitute for the two 3.6v 160MAH options as they are out of stock until mid May  
Plus these solutions would involve slightly less fidling 

This one is 7.2v 320MAH:-

http://www.buyabattery.co.uk/alarm-bell ... vh6a6.html

OR

7.2v 160MAH:-

http://www.espspecialbatteries.co.uk/ba ... -7-75-722E


----------



## Hoggy

Hi, Either should be fine, 320 would be better if there's space.
Hoggy


----------



## John-H

Yes but be careful of the size.


----------



## Reasty

just pulled my siren out as it wasnt working,i seem to have the later style one which is longer and has different style batterys in it (not the button ones) i found if you pulled back the side carpet in the boot there where 2 8mm nuts that held it in place so very very easy to remove,no feeling around inside for me.
After opening the alarm up i found the battery had leaked so badly that the entire circuit board was gungy and black  
So no quick fix for me,ive just ordered a new one from audi at the premium of £132 including vat,but atleast i shouldnt have any more problems with it and its another thing ticked off the list.


----------



## Hoggy

Hi Reasty, check the plug/loom for corrosion before reconnecting new one as corrosion known to creep along loom & ruin that.
Hoggy.


----------



## Reasty

Thanks hoggy I shall make sure I check it all before fitting the new siren,last thing I want is this one dying in a matter of weeks,especially at this price! :wink:


----------



## John-H

You'd have thought they would sort leakage problems out with the redesign. Even a plastic bag around the battery would help.


----------



## warrenstuart

John-H said:


> You'd have thought they would sort leakage problems out with the redesign. Even a plastic bag around the battery would help.


And then the sales of spares would drop... method in the madness IMO :?

Warren.


----------



## Reasty

John-H said:


> You'd have thought they would sort leakage problems out with the redesign. Even a plastic bag around the battery would help.


yes john you would of thought that after going through all that trouble to redesign it they would of acctually sorted out the underlining problem that was there in the first place but it appears not as the circuitboard in mine is trashed! the whole thing is black and gungy,ive looked at the wiring loom and the connector and there is no sign of corrosion there at all so it must of been the battery thats done this


----------



## jhoneyman

Reasty said:


> John-H said:
> 
> 
> 
> You'd have thought they would sort leakage problems out with the redesign. Even a plastic bag around the battery would help.
> 
> 
> 
> yes john you would of thought that after going through all that trouble to redesign it they would of acctually sorted out the underlining problem that was there in the first place but it appears not as the circuitboard in mine is trashed! the whole thing is black and gungy,ive looked at the wiring loom and the connector and there is no sign of corrosion there at all so it must of been the battery thats done this
Click to expand...

Do you have any pics - Always good to see the state these get in.


----------



## Reasty

I do have pictures yes but have no idea how to post them on the forum


----------



## Hoggy

Reasty said:


> I do have pictures yes but have no idea how to post them on the forum


Hi,
To show us a pic.
Sign up with http://www.photobucket.com, its free. 
Upload pics from you PC using "Browse", click the "cog wheel" & click "share links" click the "IMG code " tag & paste into your post.
Hoggy.


----------



## Jaylad

I heard three 'beeps' the other day,is this a sign of the battery on the way out ? It only happened once in four days,how long have I got to change it ?


----------



## Hoggy

Jaylad said:


> I heard three 'beeps' the other day,is this a sign of the battery on the way out ? It only happened once in four days,how long have I got to change it ?


Hi, 3 beeps from the rear on switching on Ign is a sign battery is failing. Remove & open up asap, probably starting to corrode already, so sooner the better, if you want to repair it.
Hoggy.


----------



## Reasty

So this is what i found this morning.


----------



## Reasty

And the back side


----------



## Reasty

The new alarm arrived at my local audi dealer today so popped over to collect it and is now back in the car and beeping like a gooden! i say beeping because that best describes what it does,not really a siren more of a "excuse me mr car thief if you hadnt noticed my alarm is going off, but if you dont tell anyone then i wont ha ha!


----------



## Jaylad

Used this guide and maplins batteries to fix mine today,no beeps on ignition :wink: 
Great guide cheers ;-)
As a side note,mine only started bleeping this week but the batteries had already started to leak and wouldn't of taken long yo ruin it.
If you have the tools/skills to do this I would just do it anyway if you want to make sure you keep your alarm chirp


----------



## warrenstuart

Jaylad said:


> If you have the tools/skills to do this I would just do it anyway if you want to make sure you keep your alarm chirp


Totally agree with what he said ^^^^ as ours worked fine last year, battery went flat on the remote last week and consequently we set the alarm off opening the car with the key but the siren didn't sound.
Took it all apart hoping to salvage it in time but too late [smiley=bigcry.gif]

Batteries had already leaked...



















and PCB damaged...










I un-soldered the -ve battery terminal, cleaned up the through-plated holes etc and soldered it back in. Also cleaned up the PCB and had a good look at it under my magnifier and it didn't seem too bad so i connected it up using my bench power supply to test before going out to purchase new batteries but it's goosed...










If your alarm siren still works and if you have the tools & ability swap the batteries do it this weekend before it's too late :?

Warren.


----------



## -Jason-

So my alarms batteries were dead so just got a second hand unit off ebay. Fitted it today and it now has sound when the alarm goes off however when I run a scan it comes up with alarm siren no communication (or something similar) any ideas?

I changed the settings so it bleeps when I lock it and I can hear the beep so all seems to be working fine so abit confused.


----------



## tommatt90

Have you cleared the code? Then rescanned? May be an old code


----------



## warrenstuart

Used but newer type A suffix alarm siren i got last year has failed already FFS [smiley=bigcry.gif]

Can't be doing with the hassle any more so off to Audi to get raped to the price of a new one... :?

Warren.


----------



## John-H

Nooooo fix it fix it fix it


----------



## tonyabacus

Read through the Forum but cannot find the answer, so can anyone tell me whether the plug on the later sirens are the same as the earlier ones. I have an early siren which has given up the ghost so looked at buying a second hand later unit and change the batteries over before installing. If they are different has anyone experience of removing pins from the old plug and inserting them into the later plug. I have a good Snap On pin removal tool that works on most plugs so saves on having to solder up wires etc.

Any advice on buying second hand also useful.
Thanks
Tony


----------



## jhoneyman

tonyabacus said:


> Read through the Forum but cannot find the answer, so can anyone tell me whether the plug on the later sirens are the same as the earlier ones. I have an early siren which has given up the ghost so looked at buying a second hand later unit and change the batteries over before installing. If they are different has anyone experience of removing pins from the old plug and inserting them into the later plug. I have a good Snap On pin removal tool that works on most plugs so saves on having to solder up wires etc.
> Thanks
> Tony


I know that the sirens were upgraded and the plugs are the same, after all the part number is slightly amended too with a product improvement.

If you go by part number you can't go wrong ( 8L0 951 605 A) This is the newer version
You can also use the A3 version : 1K0951605C

However if you are wanting to say use an alarm from a Mk2 it wont work due to the technology used etc.


----------



## Boris1

Later model siren with A suffix fits straight in - got one from a scappy £20 fitted the other night in 10 mins, shouldn't have bothered really it's not an alarm it's a barely audible beep!!!


----------



## Boris1

Should have said - had to change the 12mm bolt to a 10mm


----------



## John-H

I can't remember anyone saying the later alarm siren connector is different. There is a link at the end of the How-To from Warren about replacing the connector if it's damaged. The pins in the siren are PCB mounted of course.


----------



## Hoggy

Hi, I fitted a later siren with 12mm bolt instead of 10mm bolt & connector the same.
Repaired the old one for future use.
Hoggy.


----------



## tonyabacus

Thanks everyone, the comment about using the Mk2 being no good, does anyone know the number as it seems there are several so I don't want to buy the wrong one.
Tony


----------



## Boris1

The one I bought was 8L0 951 605 A fitted straight in


----------



## warrenstuart

Boris1 said:


> The one I bought was 8L0 951 605 A fitted straight in


+1 for this ^^^^ fitted and straight in no messing at all.

Warren.


----------



## jhoneyman

tonyabacus said:


> Thanks everyone, the comment about using the Mk2 being no good, does anyone know the number as it seems there are several so I don't want to buy the wrong one.
> Tony


I did give the numbers above :roll:


----------



## tonyabacus

Thanks John, I saw the numbers but wanted to check there were no others
Tony


----------



## tonyabacus

Have been looking at alarms as suggested, does anyone know how to date the alarm, do the codes stamped on the front give any indication of age, as there seems little point in fitting an alarm where the batteries are about to expire. It seems the battery lasts about 10 years, is that about right can anyone confirm?
Tony


----------



## Hoggy

tonyabacus said:


> Have been looking at alarms as suggested, does anyone know how to date the alarm, do the codes stamped on the front give any indication of age, as there seems little point in fitting an alarm where the batteries are about to expire. It seems the battery lasts about 10 years, is that about right can anyone confirm?
> Tony


Hi, No idea how to date, but my original lasted 7 years, replacement, not new, still working after 8 years.
Original has been repaired using the "How To"
Will have look at my original tomorrow for any date stamp etc.
Hoggy.


----------



## jiver

just removed mine.
has been dead for a while (a year?) so not sure if I will cut it open or not - will research batteries/replacements first

I am 2nd owner and to my knowledge it hasn't been replaced, so might have got 13 years out of it (not so cold here).
alternatively it might have been replaced before I bought it in 2007.

anyway here is a pic with what looks like a data stamp - 0202002 which might correspond to my Feb 2002 model year.
the only other thing that looks like a year is the 08, but that is after I bought the car so that's not it.


----------



## dave250TT

Hi, When you open the siren up the date stamp is on the alarm speaker! not very convenient I know but that's where it is, cheers Dave


----------



## ryanmtt

Does anyone know if the batteries are the same in the later unit

Cheers


----------



## Roadrunner6623

Great write up. 
Any idea if these batteries for drones would also be suitable? 
https://www.ebay.co.uk/itm/142098973604


----------



## pcbbc

Roadrunner6623 said:


> Great write up.
> Any idea if these batteries for drones would also be suitable?
> https://www.ebay.co.uk/itm/142098973604


Not unless you want a fire.
LiPo and NmHi batteries have very different charging characteristics. NiMh will withstand constant trickle charging for example, so the alarm module is probably set up to provide that.
LiPo are damaged by overcharging, and require use of a dedicated charge controller which stops the charge when the target voltage is reached. Otherwise at best the cell will be damaged, at worst it will overheat and catch fire.
Think Samsung Galaxy Note 7....


----------



## dave250TT

Tried two different sirens on mine one new off ebay? and a second hand one, with no luck still not working and have also tried the replacement battery fix as on the forum, wondered if a broken wire in the drivers door harness could effect the alarm working?


----------



## John-H

dave250TT said:


> Tried two different sirens on mine one new off ebay? and a second hand one, with no luck still not working and have also tried the replacement battery fix as on the forum, wondered if a broken wire in the drivers door harness could effect the alarm working?


Lock the car with the driver's window open and watch the flashing LED on the door. It should flash fast from first locking then start to flash slowly after a few seconds. The alarm is now armed. So stick your arm in through the window and wave it about. The alarm should now sound, accompanied by the hazards flashing. If you get hazards but no siren then your siren is not working.

You may have a damaged connector to the alarm siren.


----------



## dave250TT

Hi John, thanks for the reply I have done exactly as you suggest and I get the hazard flashes but no alarm! so pointing to the siren again! maybe best to bite the bullet and buy a new one from Audi? Just thought of something else, John could the siren be switched off? needing VCDS to activate it? cheers Dave


----------



## John-H

I don't think you can disable it as far as I know. You can get it to chirp when locking with VCDS or VAG-COM. Don't forget to check the connector though as it's not uncommon for acid from a leaking battery to eat away even completely the contacts on the wiring loom connector. Make sure all three are there and bright metal.


----------



## milnei

My 2004 3.2 TTR that I recently bought also has a non functioning Alarm, and the usual fault code on my OBDeleven (VDCS/VAGCOM for the poor). I opened up the case, and the batteries had done their usual trick of spewing nasty guuk all over the PCB . Fortunately the harness and connector are fine.

Bought a ####C part off eBay to replace my ####A but no joy, not a peep, so I suspect this one is also toast. Debating whether to return the item to the seller as faulty, or take my chances and open it up in the hope that the batteries haven't leaked and can just be replaced.

Is there any non destructive way of finding out if the PCB is OK or not? Like I said, my original one looked fine on the outside, and the harness and connector were clean, so that's not going to be a clue.

Also, what's the coding to enable the chirp on lock/unlock? I can do it with OBDeleven but just need the module and adapter codes etc....

Thanks.


----------



## John-H

The case is welded up pretty tight. I can't think of a non destructive means of having a look inside. Even drilling a small hole for an endoscope would leave a mark.

For the chirps - have a look in the Knowledge Base I think under Vag-Com but ultimately it takes you to Wak's website where there is a Vag-Com section under one of his How To links.


----------



## SilverArrow

I was going to replace the battery BUT... the alarm box isn't even there. Haa!

No flashing hazards on lock or unlock. The red door LEDs do flash though.

So, would you think it was completely removed or for whatever reason a location change but with empty batteries still?
Getting no error codes. Maybe deleted from the ECU too. Weird huh?


----------



## John-H

European models had the alarm in the boot on the left over the wheel arch behind the trim with an access door - reach forward of that. US models had an extra horn at the front and no siren I believe.


----------



## SilverArrow

Thanks. Yes, mine is Euro 2000 225Q APX, no retrofit ESP(may be a clue). There was no black box behind left taillight. Removed the taillight and checked it thoroughly with a flashlight. I can't even see an unplugged cable there.

What I'm trying to figure out is if red door LEDs are connected to that box(possible relocation) or are they driven by another unit around console. Or, early models didn't have it at all maybe?


----------



## John-H

Hmmm... Mine is a European APX 1999 and I have one. It's connected to the CAN bus so serial communications. In theory it could be relocated. Mine has ESP retrofit but the alarm was not part of that.

Have you tried locking the car with the remote with the window open - wait until the LEDs flash slow, then stick your arm in and wave it about? Your alarm should sound and the hazards flash.


----------



## milnei

Hmm, I think I'll hack my eBay one open, and if it's also ruined then it's plan B.....

Plan B.....

Use the car horn in sequence with the indicators. Obviously, only without the ignition being on, and then only when the car is locked and after the indicators have stopped flashing to confirm the car has locked......

So a perm 12v feed (which is active 10 seconds after a mechanical switch is closed by the locking solenoid for the central cubby hole on the roadster) feeds the horn (via a diode to prevent back feed) through a relay triggered by the indicator bulbs. But that 12v perm feed is through the NC terminal of a relay which is opened by the ignition feed.

Sounds complicated but I've got it drawn out and I think it'll work. Would like not to have the mechanical switch off the locking solenoid, but need some feed to signal that the doors are locked.....


----------



## milnei

Opened up the eBay unit and luckily the batteries were still clean, completely discharges, but clean. So off to Maplins I go and buy the last two 3.6v 160mAh PCB NiMH batteries.

Done all my un soldering, and before putting in the new ones, I made sure they were fully charged but trickle charging them, got another 80mAh into them.

So soldered them in, and hot glued the case together. Popped the new unit back in, expecting the siren to go off as it has done for others, but nothing. OK I thought, let's lock and unlock, and see if I get any chirps, again nothing. So final test, open the windows, lock the doors and set the alarm off.

Unfortunately still nothing, nada, phut! 

I'm guessing it's nothing to do with the fact it's a ####C instead of ####A. One thing I did notice is that the behaviour of the door LEDs hasn't changed.

Firstly the drivers door one doesn't come on at all, is this normal, is it just the nearside one that lights up?
Secondly, it's around 8 seconds before the passenger LED starts flashing after locking the car. Then it's a fast flash for around 2 seconds, then it slows down to a quick flash for around 25 seconds, then the normal slow flash after that.

Is this behaviour normal? Like I said, it's no different with or without the siren fitted. Is there something else wrong? Is the fact that the driver's door LED does nothing a problem or not??

HELP please......


----------



## Hoggy

Hi, Both door LEDs should flash in the sequece you've stated, slow flash after a few seconds shows system is armed.
Siren working or not has no affect on system being armed.
Have you checked there is no corrosion on the alarm plug/socket/loom.
Hoggy.


----------



## John-H

Do the hazards not flash when the alarm should be sounding after you've waved your arm in through the window? If the alarm is not being triggered then that would explain the siren not sounding too of course.


----------



## milnei

Thanks for the replies.

The hazards do flash when the alarm is triggered, and the plug and harness are fine, no corrosion at all.

Maybe my second unit is fried after all, even though the circuit board looked fine. I'll need to check why the drivers door LED isn't working though. And did someone mention that the siren might need synchronising with the system by disconnecting the battery, might try that too.

Otherwise it's Plan B again :?


----------



## John-H

If the hazards are flashing then the alarm is triggered and your siren should have received the serial data command to start sounding. Either the signal isn't getting through (look into loom connector to check the female connections are not corroded from previous leaking acid - they should be shiny) or the siren battery is flat (but I think you said it was charged).

A reset of the siren occurs on power-up of the device. There's no "synchronisation" with the car as such but the module driving the siren (along with others) will be reset on reconnection of the car battery, so removing any locked up states they may have got into.

Make sure you have your radio code and be aware you will have to reset your window auto wind extents. Make sure you reconnect the battery cleanly with a single reconnection (no bouncing lead with multiple sparks - one firm reconnect is needed for a clean reset).


----------



## mercflyer

Hi there
wonder if any one able to assist, have been looking at resolving alarm siren on my TT very similar issues as mentioned my original siren simply did not work tried enabling it then setting it of by waving arm in side car, this made indicators flash and nothing else no alarm, bought used one from ebay same thing. Decided to look at contact points on my original alarm and noticed centre pin 2 was corroded so scraped clean with small screw driver, re connected and now get a quite pulsating electrical noise, set alarm waved arm inside still no siren going off, only indicators flashing but did notice the pulsating electrical noise stopped, when disabled alarm, ie unlocked car the electrical noise, beat returned. connected 2nd siren from ebay and nothing not even pulsating quite noise. But noticed the pins have no clean surface at all, decided not to attempt to clean them as plan on returning it. Disconnected the original alarm as did not want to risk electrical pulse making suspect noises. Any one able to explain the likely cause of the quite pulsating noise ? thanks


----------



## Hoggy

Hi, Check the plug/loom as that can corrode as well & creep up into the loom.
Hoggy.


----------



## John-H

In addition to loom connection issues, presuming the siren battery has charged, the funny noise could indicate that leaking acid has caused malfunction. If the battery won't charge fully low voltage could also be the issue.


----------



## Allspeed

Unless my ones not working properly, I think calling it a siren it a bit of overkill. When I set mine off it wouldnt scare anyone away. It's a very very quiet chirping, very quiet.
Why didn't Audi make the horn sound, would have been a simple cheap effective deterent surely?


----------



## John-H

They did for the US market apparently. I think here the issue was influenced by nuisance to neighbours and also gaining Thatcham Cat 1 approval regarding a self powered siren independent of the main car battery.


----------



## David C

ryanmtt said:


> Does anyone know if the batteries are the same in the later unit


Same voltage, but different.
I got a pair of the recommended batteries and cut my later unit open to replace them...... ended up glueing it back together with the original batteries still in place!!


----------



## mercflyer

thanks for responses, think will take the old faulty unit apart and see just how much damage has taken place to see if worth trying to salvage it.......


----------



## gerontius

Guys,
My old siren is kaput, the battery leak has damaged the pcb beyond repair.
I've bought a 1K0 951 605C real cheap (£15) from a breaker, but that doesn't work either.
I do know that one of the pins on my loom plug is a bit corroded, just waiting on delivery of a new plug kit.

Two questions: 
Is the 1K0 961 605C a straight swap for the old 8L0 951 695 ? And, if so:
Are the batteries on the 1K0 961 605C replaceable in a similar way if I open it up, in the hope that the pcb will be good ?

Thanks

John


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## Hoggy

Hi, It is straight swop other than the securing bolt is slightly bigger diam.
No idea if batteries are the same but my replacement 605c has lasted much longer than the original 605.
Hoggy.


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## gerontius

Perfect Hoggy thanks.

If it doesn't work after I've renewed the harness plug, I'll open it up & post some pics.

Twycross tomorrow !

John


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## gerontius

So I fitted a 1K0 951 695C (bought off eBay breaker) . The pins were spotless. Also renewed the plug on the loom as one pin was corroded and it had travelled up the brown wire quite a bit. New siren doesn't work either.
Cut it open to look at the battery, which is clean & measures 7.8 volts.
Not sure what to try next !
Are there any settings in VCDS I should check ?


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## Hoggy

Hi, Reconnect the siren, check the voltage while activating the alarm, you may find the battery voltage drops to zero ish meaning it requires leaving connected to recharge the batteries.
Hoggy.


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## John-H

Yes. It should also be getting a short message via serial comms when your alarm triggers. Set that off by locking the car with the window open, waiting for the door LED to go from quick flash to slow flash then wave your arm about through the window. The hazards flashing confirms that the alarm is triggered.


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## milnei

Just an update on my progress in getting the alarm to sound.

Seems like you MUST fit like for like when it comes to part numbers. Just because one unit 'looks' the same it appears that it may be talking a different language if the part numbers are different.

I can't remember what my original fried alarm sounder was, but I phoned Audi and they told me that for my 04 plate V6 I needed 8L0 951 605A. I went a bought a 1K0 951 605C, which looked exactly the same, and replaced the dead batteries, but the sounder didn't work, and I had 'no communication with alarm horn' on my diagnostics.

I then bought off ebay 8L0 951 605A, hoping that the batteries weren't dead, or at least if they were dead that they hadn't leaked all over the circuit board. I fitted it and wehey, a loud beep-beep-beep when I trigger the alarm.

All I need to do now is figure out how to get the audible confirmation on locking and unlocking. I have Wak's guide on how to do it with VagCom, but I'm using OBDeleven for my coding, so has a different interface. I'm hoping it's a similar process with the same magic numbers.

By the way, anyone have need for a reconditioned 1K0 951 605C with brand new batteries??


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## Hoggy

Hi Milnei, Perhaps the 605c is knackered anyway which is why it didn't communicate/work. 
Hoggy.


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## milnei

Hoggy said:


> Hi Milnei, Perhaps the 605c is knackered anyway which is why it didn't communicate/work.
> Hoggy.


Possibly, but when I opened it up to fit new batteries, the circuit board was nice and clean with no visible damage.

I should have thought on really, I work in the motor industry and we only change part numbers on a revision of a part if we absolutely have to, and it's usually because the new part isn't interchangeable with the old one, even if they look completely the same. :roll:


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## John-H

Hoggy said:


> Hi, It is straight swop other than the securing bolt is slightly bigger diam.
> No idea if batteries are the same but my replacement 605c has lasted much longer than the original 605.
> Hoggy.


Hi Hoggy,

What was the full part number for the one that worked for you?

The original is 8L0 951 605A


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## John-H

milnei said:


> Just an update on my progress in getting the alarm to sound.
> 
> Seems like you MUST fit like for like when it comes to part numbers. Just because one unit 'looks' the same it appears that it may be talking a different language if the part numbers are different.
> 
> I can't remember what my original fried alarm sounder was, but I phoned Audi and they told me that for my 04 plate V6 I needed 8L0 951 605A. I went a bought a 1K0 951 605C, which looked exactly the same, and replaced the dead batteries, but the sounder didn't work, and I had 'no communication with alarm horn' on my diagnostics.
> 
> I then bought off ebay 8L0 951 605A, hoping that the batteries weren't dead, or at least if they were dead that they hadn't leaked all over the circuit board. I fitted it and wehey, a loud beep-beep-beep when I trigger the alarm.
> 
> All I need to do now is figure out how to get the audible confirmation on locking and unlocking. I have Wak's guide on how to do it with VagCom, but I'm using OBDeleven for my coding, so has a different interface. I'm hoping it's a similar process with the same magic numbers.
> 
> By the way, anyone have need for a reconditioned 1K0 951 605C with brand new batteries??


Thanks for that - I've added a warning. It may be possible to use the wrong siren if its processor chip is substituted for the original as that will have been programmed with the correct software.


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## Hoggy

Hi, 8L0951605 is the original siren & not been avail since Nov 2003, 8L0951605A is the replacement.
I will have to check what I replaced my 605 with but it is still working after 9 years & was S/H from forum.
It had the larger diam fixing bolt.
Hoggy.


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## pc759

John-H said:


> milnei said:
> 
> 
> 
> Just an update on my progress in getting the alarm to sound.
> 
> Seems like you MUST fit like for like when it comes to part numbers. Just because one unit 'looks' the same it appears that it may be talking a different language if the part numbers are different.
> 
> I can't remember what my original fried alarm sounder was, but I phoned Audi and they told me that for my 04 plate V6 I needed 8L0 951 605A. I went a bought a 1K0 951 605C, which looked exactly the same, and replaced the dead batteries, but the sounder didn't work, and I had 'no communication with alarm horn' on my diagnostics.
> 
> I then bought off ebay 8L0 951 605A, hoping that the batteries weren't dead, or at least if they were dead that they hadn't leaked all over the circuit board. I fitted it and wehey, a loud beep-beep-beep when I trigger the alarm.
> 
> All I need to do now is figure out how to get the audible confirmation on locking and unlocking. I have Wak's guide on how to do it with VagCom, but I'm using OBDeleven for my coding, so has a different interface. I'm hoping it's a similar process with the same magic numbers.
> 
> By the way, anyone have need for a reconditioned 1K0 951 605C with brand new batteries??
> 
> 
> 
> Thanks for that - I've added a warning. It may be possible to use the wrong siren if its processor chip is substituted for the original as that will have been programmed with the correct software.
Click to expand...

Thatll be why my golf iv alrm doesnt work then which i got as a cheapo for my missing original


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## jiver

howdy, haven't been here for a bit.
I removed my siren a few years back as beyond repair.
I saw this *new* siren on evilbay.
https://www.ebay.com.au/itm/Alarm-Syste ... 1438.l2649

which they say suits for AUDI TT, Mk2 tho

I was wondering if anyone had come across a new one from China to suit a Mk1?
I can't bring myself to pay AUD$400+ for one


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## milnei

Based on my experience, if the part numbers aren't a perfect match, then be prepared for failure 

I'd say your best bet would be to buy a used one of ebay and try it.
A - If you're VERY lucky it'll work (but might need a couple of hours/days connected to the harness to charge the internal batteries).
B - If it doesn't work then either send it back and try another one, or open it up and if you're QUITE lucky the circuit board will be OK and all you'll need to do is replace the batteries as described elsewhere.
C - if you're UN lucky the board will be fried and it's scrap.

The original on in my car was 'C', I then bought one that was 'B' but as it wasn't like for like, my new batteries didn't make it work in my car. Finally got lucky with 'A'.


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## John-H

I asked at my Audi dealer if they could hang onto a scrap one for me. They only recycle them. That way you can fix it if yours is too badly damaged. At least if it's out of a TT with the same part number the programming will be the same.


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## jiver

thanks ppl
guess that's a no then.

I have had an evilbay search running for a few years for a scrap one but nothing in Australia has shown up, let alone in my area. see some from overseas, mainly Germany, but I could spend a fortune on return postage before getting lucky.


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## jiver

saw a 8L0 951 605*A* one yesterday 
can anyone confirm/deny that they are two piece as opposed to the sealed unit of the 8L0 951 605
can come apart to replace batteries?
or was I imagining things?


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## John-H

If you look further up this thread here:

viewtopic.php?f=2&t=73315&p=5001529#p5001529

As "sheepshearer" says you can cut the 8L0 951 605A open with a knife to change the batteries - so they are sealed but obviously can still suffer from leakage and be fixed.


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## jiver

thanks for that
I hadn't gone back enough pages.
the A model looked to have a recess join whereas the non A model is obviously sealed.

(shame the photos are starting to disappear, global issue)


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## John-H

The photos disappearing has always been a problem but Photobucket has highlighted the issue. If you find a missing picture here that you need post a link to the post and I'll see if I can restore it.


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## Proton91

Is there a possibility to find the SMD part numbers?


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## pcbbc

Proton91 said:


> Is there a possibility to find the SMD part numbers?


Plugins to fix this issue for Firefox and Chrome


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## Pukmeister

Something else to investigate and fix as necessary.

This forum just keeps on giving, thanks for the help !


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## Pukmeister

Just fitted a new rear number plate and some LED lights, so I thought I would trigger the alarm and see what happens:

Well, the sounder works on my car, but it is really pathetic. I would probably sleep through it whilst a car thief drove away.

Tested the window close when holding the lock key feature, that works too. Result !


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## DC240S

Dusting of this great thread!

Thanks to the OP

DC


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## Sandy

Excellent fix post


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## Ben180

Sorry for this probably dumb question, I have scanned through some of these pages but there is just too many.

Can I remove the siren and just leave it out, will the doors still work etc? I just don't think its necessary for a 15 year old car that I leave with nothing in and sits at home most of the time in a little village to even have an alarm.


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## Hoggy

Ben180 said:


> Sorry for this probably dumb question, I have scanned through some of these pages but there is just too many.
> 
> Can I remove the siren and just leave it out, will the doors still work etc? I just don't think its necessary for a 15 year old car that I leave with nothing in and sits at home most of the time in a little village to even have an alarm.


Hi, Yes, remove it, will save the plug & loom corroding if left in place & not working.
Hoggy.


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## Ben180

Hoggy said:


> Ben180 said:
> 
> 
> 
> Sorry for this probably dumb question, I have scanned through some of these pages but there is just too many.
> 
> Can I remove the siren and just leave it out, will the doors still work etc? I just don't think its necessary for a 15 year old car that I leave with nothing in and sits at home most of the time in a little village to even have an alarm.
> 
> 
> 
> Hi, Yes, remove it, will save the plug & loom corroding if left in place & not working.
> Hoggy.
Click to expand...

Thanks Hoggy


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## Adamwtt

Ben180 said:


> Hoggy said:
> 
> 
> 
> 
> 
> Ben180 said:
> 
> 
> 
> Sorry for this probably dumb question, I have scanned through some of these pages but there is just too many.
> 
> Can I remove the siren and just leave it out, will the doors still work etc? I just don't think its necessary for a 15 year old car that I leave with nothing in and sits at home most of the time in a little village to even have an alarm.
> 
> 
> 
> Hi, Yes, remove it, will save the plug & loom corroding if left in place & not working.
> Hoggy.
> 
> Click to expand...
> 
> Thanks Hoggy
Click to expand...

The thread that keeps on giving! Thanks Hoggy for this last one.

Haven't checked for corrosion yet, but think I'm going to remove mine and avoid potential issues and rule it out as a potential drain on my main battery.


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## Quattro99

Apologies in advance if its already been mentioned (I wasn't going to search 26 pages).

After finally getting my hands on a working, but rattling (I presume its bits of oxidised corrosion) siren, I've been searching for replacement batteries and found a ready made solution from ESP batteries, quote...

7.2V 6*160MAH OVAL STACK+LEADS
"Audi Alarm Battery.
Our replacement for the two
(now discontinued Emmerich )
3.6v push fit batteries N3H170
This requires some minor modification to fit but electicaly does the same job."

https://www.espspecialbatteries.co.uk/b ... -7-75-722F

It has the batteries already connected and encased with two wires protruding, so minimal soldering required. Due to past experience I wasn't looking forward to soldering the two stacks together. I've just ordered one for my fix.

Hope this helps somebody.


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## Hoggy

Quattro99 said:


> Apologies in advance if its already been mentioned (I wasn't going to search 26 pages).
> 
> After finally getting my hands on a working, but rattling (I presume its bits of oxidised corrosion) siren, I've been searching for replacement batteries and found a ready made solution from ESP batteries, quote...
> 
> 7.2V 6*160MAH OVAL STACK+LEADS
> "Audi Alarm Battery.
> Our replacement for the two
> (now discontinued Emmerich )
> 3.6v push fit batteries N3H170
> This requires some minor modification to fit but electicaly does the same job."
> 
> https://www.espspecialbatteries.co.uk/b ... -7-75-722F
> 
> It has the batteries already connected and encased with two wires protruding, so minimal soldering required. Due to past experience I wasn't looking forward to soldering the two stacks together. I've just ordered one for my fix.
> 
> Hope this helps somebody.


Hi, A little expensive but a useful replacement, a good find.
Next time I fix one I will fit the batteries externally.
Hoggy.


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## silverbug

Quattro99 said:


> Apologies in advance if its already been mentioned (I wasn't going to search 26 pages).
> 
> After finally getting my hands on a working, but rattling (I presume its bits of oxidised corrosion) siren, I've been searching for replacement batteries and found a ready made solution from ESP batteries, quote...
> 
> 7.2V 6*160MAH OVAL STACK+LEADS
> "Audi Alarm Battery.
> Our replacement for the two
> (now discontinued Emmerich )
> 3.6v push fit batteries N3H170
> This requires some minor modification to fit but electicaly does the same job."
> 
> https://www.espspecialbatteries.co.uk/b ... -7-75-722F
> 
> It has the batteries already connected and encased with two wires protruding, so minimal soldering required. Due to past experience I wasn't looking forward to soldering the two stacks together. I've just ordered one for my fix.
> 
> Hope this helps somebody.


Thanks for posting that, only this morning I'd been looking at the batteries used in the siren and the Varta equivalents are about £7 each so that's already £14 plus the need to join them together :? .


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## Quattro99

> 7.2V 6*160MAH OVAL STACK+LEADS
> Thanks for posting that, only this morning I'd been looking at the batteries used in the siren and the Varta equivalents are about £7 each so that's already £14 plus the need to join them together :? .


You're very welcome, thats all I could find too. Glad the info came in useful to someone


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## silverbug

Quattro99 said:


> You're very welcome, thats all I could find too. Glad the info came in useful to someone


It was so helpful I've bought one 8) .
I fitted a working second-hand siren last year to my car because this how-to just looked too complex with all the faff with the batteries.
If/when this current siren packs up it appears the repair should be fairly simple with this ready prepared battery  .


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## PlasticMac

silverbug said:


> Quattro99 said:
> 
> 
> 
> You're very welcome, thats all I could find too. Glad the info came in useful to someone
> 
> 
> 
> It was so helpful I've bought one 8) .
> I fitted a working second-hand siren last year to my car because this how-to just looked too complex with all the faff with the batteries.
> If/when this current siren packs up it appears the repair should be fairly simple with this ready prepared battery  .
Click to expand...

I think it'll be when, not if ... 
It does look like this battery pack will fit inside, there is a a little bit of spare room. 
Mac.


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## John-H

The battery pack seems to be a copy of what I made from two separate batteries. Should be enough room therefore.


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## silverbug

It's a bit of a dilemma , leave current siren as it is , allow it to die and then repair it or take the perfectly functioning siren out now and put the new battery in?
Alternatively , buy a working one on eBay now and do the battery repair , although the prices being asked for those old sirens seems to be going up and up :? .


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## PlasticMac

I think it depends on the version of siren your car has. If it's an early one, which has NiCad batteries, then fitting NiMH replacements is not a long term fix, as the NiCd charging circuit doesn't suit them. If you have the later version, then check the date code, and if it's 10+ years old, change the battery when it's convenient. Rather than waiting for the inevitable failure when it's cold and wet etc.
If you have an old version, buy a used late one, and fit a new battery before swapping it. 
Mac.


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## silverbug

PlasticMac said:


> I think it depends on the version of siren your car has. If it's an early one, which has NiCad batteries, then fitting NiMH replacements is not a long term fix, as the NiCd charging circuit doesn't suit them. If you have the later version, then check the date code, and if it's 10+ years old, change the battery when it's convenient. Rather than waiting for the inevitable failure when it's cold and wet etc.
> If you have an old version, buy a used late one, and fit a new battery before swapping it.
> Mac.


Cheers , I threw away the original 605 which had got into a heck of a state internally and had also corroded the wiring quite extensively , so after loom repairs I fitted a fully working 605A from about 2008 , which one year on is working BUT I do get an "undervoltage" fault code on the alarm siren whenever I do a VCDS scan .
So , I suspect the batteries in that one are failing too.
Perhaps it makes sense to put the new battery pack when it arrives in this existing siren , at least I know the circuit board is OK as it still works.


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## PlasticMac

Yes, as the battery fades, the risk of a leak, and of pcb damage increases, which might rule out a battery swap. So, sooner rather than later.
Mac.


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## Quattro99

PlasticMac said:


> Yes, as the battery fades, the risk of a leak, and of pcb damage increases, which might rule out a battery swap. So, sooner rather than later.
> Mac.


Yes after cutting my original one open I found it was too far corroded to the extent that bits of the board had fallen off! The connector pins had started to corrode but fortunately the connector plug is okay.

I bought a used one, but it didn't work I already suspected this because corrosion fell out of the connector area when it arrived!

Luckily my next one worked, but out of caution I split it open. I found one of the batteries had leaked, but it had only damaged the connector terminal and should be okay now that I've cleaned off the corrosion, it was obviously still making contact for the siren to work. The board looks okay, the acid didn't leak onto the business side.

So with it being third time lucky and finding working replacements harder to find, I would recommend replacing the batteries "sooner rather than later" too.

With regards to long term maintenance and replacement, Hoggy has a bright idea of putting the batteries outside of the siren.

I suppose you could also attach the battery pack with block connectors, so no need for any future faffing.


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## Hoggy

Hi, I think it may be time to replace my batteries, still works but been there many years.
I will get a 6 pack of AAA, & connect them externally with plug/socket.
Long lead & could replace next time without removing the rear light.
Hoggy.


----------

