# Switched & Perm Live - Earth - For hands free kit install



## jayTTapp (Dec 9, 2008)

I want to install a hands free kit which requires a switched live (on with ignition) permanent live and earth.

I read plenty about "bus bar" but can find no picture or guides on how to access it, or where to connect the wires. The link that many refer to is currently down.

Please could someone point me in the right direction. I could take them from the back of the headunit, a concert II. But even with a wiring diagram of that it's not proved possible - by me anyway.

Below is a picture of the wiring diagram, I have an ISO plug on the kit that goes to the headunit labelled socket 1. But
the handsfree kit will not power up so I can only assume a earth is found on this plug. The hands free kit works as tested oon another car.

Thanks

Jay


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## triplefan (Sep 3, 2008)

I had no luck hooking up to a switched power supply from the radio supply loom.

Best to go back to the fuse box, and tap into number 1 (heated mirror and washer jets) it's a 10 amp, and hardly ever gets used.

If you want to do it properly, insert an inline fuse of a lesser value as 10 amps is a bit much for a hands free.

I'm no electrician, but reckon 2.5 would be fine


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## fishface (Nov 25, 2006)

I ytook my switched live off the buz bar, I think it's the left terminal if I remember correctly but you need an in line fuse straight after.
You have to take off the panel under the steering wheel and you will see all the main electrical connections and relays etc.

Another way to do it is use one of these, though not a cheep option http://www.fitbluetooth.co.uk/files/details.php?id=232


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## jayTTapp (Dec 9, 2008)

triplefan said:


> I had no luck hooking up to a switched power supply from the radio supply loom.
> 
> Best to go back to the fuse box, and tap into number 1 (heated mirror and washer jets) it's a 10 amp, and hardly ever gets used.
> 
> ...


Thanks, I assume ther must be a permanent live presented somewhere to the fuse box??


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## jayTTapp (Dec 9, 2008)

fishface said:


> I ytook my switched live off the buz bar, I think it's the left terminal if I remember correctly but you need an in line fuse straight after.
> You have to take off the panel under the steering wheel and you will see all the main electrical connections and relays etc.
> 
> Another way to do it is use one of these, though not a cheep option http://www.fitbluetooth.co.uk/files/details.php?id=232


So can you tell me how to access the bus (Buz) bar. If it's underneath the steering wheel and that trim needs to be removed. Is there a how to on removing that trim??

I liked the idea of the phantom live module your link took me to - but I spoke to someone who put me off one of those. As it works by monitoring current flow from the battery, so in the summer no lights, heating etc ok - but come the winter months and all those things are in use the current flow drop and the unit things you've turned off your ignition and cut the power.

Thanks Jay


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## Bikerz (Aug 23, 2008)

triplefan said:


> I'm no electrician, but reckon 2.5 would be fine


2.5 amp would give u 25watts at 12v. Power is current x voltage.

If you are after a earth just connect to any bit of metal on chasis


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## jayTTapp (Dec 9, 2008)

I've spoken to a technical person and he has said that my bluetooth kit requires perm live and switched live for it to work. That gives me the answer as to why when I only connected the perm live and earth in the picture below....it didn't work.

Has anyone connected to the switched live on plug 3 in the picture below. I just don't understand how there can't be a switched live going to the headunit. As the headunit switches on and off on the ignition.


Thanks Jay


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## Spandex (Feb 20, 2009)

jayTTapp said:


> I just don't understand how there can't be a switched live going to the headunit. As the headunit switches on and off on the ignition.


The answer to your question is on that pinout. The CAN bus is used to tell the head unit when the ignition is on or off (amongst other things). This is why your head unit turns off as the key is drawn out of the ignition barrel, rather than when it's turned to the 'off' position.


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## jayTTapp (Dec 9, 2008)

Spandex said:


> jayTTapp said:
> 
> 
> > I just don't understand how there can't be a switched live going to the headunit. As the headunit switches on and off on the ignition.
> ...


Hi Spandex,

As your explanation of either pins is exactley what I want, does that mean I can take a switched live from one of those pin then??

Thanks Jay


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## jayTTapp (Dec 9, 2008)

jayTTapp said:


> Spandex said:
> 
> 
> > jayTTapp said:
> ...


So can I use of of those switched live pins??
Anyone

Thanks Jay


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## gadgetboy38 (Mar 9, 2005)

It's probably best to tap into the bus bar under the dash, you want to tap into 75x for the switched feed and either of the feeds next to it for a constant live.


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## jayTTapp (Dec 9, 2008)

gadgetboy38 said:


> It's probably best to tap into the bus bar under the dash, you want to tap into 75x for the switched feed and either of the feeds next to it for a constant live.


The bus bar sounds good...as other have mentioned it.

You have gone that step further as to mention what exactley I need to tap into.

But how do I access the bus bar??

What trim needs to be removed??

Exactley behind what is it located??

Thanks Jay


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## Spandex (Feb 20, 2009)

jayTTapp said:


> So can I use of of those switched live pins??
> Anyone
> 
> Thanks Jay


There isn't one, that's the problem. The CAN bus provides a signal that tells the stereo to switch on or off (more like standby than actually powering off). It's not a 12V high/low that you could use in the same way you'd use a switched live feed, it's a data bus carrying a number of different signals. To do it 'properly', you would need an adaptor which recognised the CAN bus ignition signal and provided a simulated switched live feed (these cost at least £50 I think). This would be serious overkill for what you want though. To do it the cheap, easy and safe way, do as Gadgetboy38 says and go for the bus bar.

Remove the trim panel below the steering wheel (just work round it undoing the screws) and you'll see the bus bar tucked up under it (I think slightly to the right of the steering column, but I could be remembering it wrong). Locate the terminal marked 75X and use that for your switched live feed. It will have a bolt sticking out with a nut on it - crimp/solder a ring terminal on the end of your wire and bolt it to the terminal for a neat job. I strongly recommend putting an inline fuse (available from Halfords) into the wire you run from here, as the bus bar is not fused and you don't want to damage your car or your handsfree if something goes wrong.


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## jas6004 (May 4, 2009)

The way that i got a switched live for my aftermarket headunit was very easy to do, if you remove the cover to the fuse box situated at drivers end of dashboard, you will see some Torque screws, just remove these screws and the fuse box will come out easily. If you check the fuse board cover and locate Fuse No 10, this is a fuse that becomes live with the ignition on, using a volt meter or similar, on the rear of the fuse box find the side of the fuse which turns off when you remove the key (test from fuse to unpainted metal bodywork) p.s make sure key is turned in ignition first.
Then using a Scotchblock you can easily connect onto this wire without the need to cut wiring loom.
I am an electrician and 2.5mm cable would be more then enough.

Hope this helps

Jas


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## Spandex (Feb 20, 2009)

Whilst there's nothing fundamentally wrong with doing it that way, the reservations I'd have would be that you're using a fuse that is also used for something else, so a) the rating may be incorrect for your handsfree kit and b) if one thing pops the fuse, you lose both of them. On top of this, I'm really not a fan of scotchlok connectors in cars. There is a risk that the vibrations in the car will loosen the connection over time and you'll start having problems. I know a lot of people use them, but I just like knowing I'm never going to have to go hunting under trim pieces, looking for a broken connection. Personally, I always solder and heatshrink (where possible) any joins or taps I make, just to be sure (although you need a gas soldering iron for this to ensure you don't damage any of the cars components with the current introduced by electric irons).


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## Hark (Aug 23, 2007)

There are 3 screws under the panel where the steering column comes up, along with the 5 or 6 on the end under the fuse cover.

Then there are 2 press clips one on the top edge directly either side of the steering column. Makes it easier if you release the column adjuster and move the wheel out and down. Just get a flat blade screwdriver in ther to pop the clips out, sometimes a bit stiff but they do just push clip in.

There are also 2 connectors on the right hand side that need unclipping.

Be careful when slacking off the nuts and I broe one of the plastic dividers. :? You'll see what I mean.

This guy had a great pic but my link to it doesn't workk anymore memberlist.php?mode=viewprofile&u=1366

Might need to go under there again this holiday for another 2 mods I have in mind. I will take pics if I do.


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## gadgetboy38 (Mar 9, 2005)

Hark said:


> Might need to go under there again this holiday for another 2 mods I have in mind. I will take pics if I do.


I'll be doing the same thing tomorrow, i'll try and remember to get some pics up.


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## Wak (May 6, 2002)

One of the best connections for Switched live is the "S-contact" on the fuse board which you can go to directly for low amp triggers or take to a relay and feed off the bus bar with a fuse.

Its Ideal for things like a bluetooth kit because it WONT switch off when you turn off the ignition.

Means you can carry on your conversation and it will switch off with the radio when the key is withdrawn from the lock.


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## triplefan (Sep 3, 2008)

Wak said:


> One of the best connections for Switched live is the "S-contact" on the fuse board which you can go to directly for low amp triggers or take to a relay and feed off the bus bar with a fuse.
> 
> Its Ideal for things like a bluetooth kit because it WONT switch off when you turn off the ignition.
> 
> Means you can carry on your conversation and it will switch off with the radio when the key is withdrawn from the lock.


Cheers Wak, don't suppose you have a pic of where this is exactly, by any chance?


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## jayTTapp (Dec 9, 2008)

Wak said:


> One of the best connections for Switched live is the "S-contact" on the fuse board which you can go to directly for low amp triggers or take to a relay and feed off the bus bar with a fuse.
> 
> Its Ideal for things like a bluetooth kit because it WONT switch off when you turn off the ignition.
> 
> Means you can carry on your conversation and it will switch off with the radio when the key is withdrawn from the lock.


As triplefan mentioned don't suppose you have a picture.

Guys many thanks for all your help - just what I wanted.

I've used a voltmeter to test the pins on my photo and they also will give me a switched live. As I'm using a third party wiring loom I don't need to cut into the original installed wires either, if I choose to go this route.
So I now have three options to choose from.

Thanks again.

Jay


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## KentishTT (Jun 28, 2007)

Spandex said:


> jayTTapp said:
> 
> 
> > So can I use of of those switched live pins??
> ...


If that is so, how does my Alpine headunit work using the same feeds?

It works in exactly the same way as the OEM Audi Concert in that it turns off when you withdraw (rather than turn) the ignition key.

Just curious...


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## Spandex (Feb 20, 2009)

Thinking about it, I read somewhere on here that early models didn't have the CAN bus. What year is yours? I guess this might apply to the OP too, after all this.


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## jayTTapp (Dec 9, 2008)

Spandex said:


> Thinking about it, I read somewhere on here that early models didn't have the CAN bus. What year is yours? I guess this might apply to the OP too, after all this.


Mine is a 54 plate so should have the CAN bus. However the two swichted live pins on my photo work when I tested with a voltmeter. I temporary wired up the bluetooth kit to one of these pins as a switched live and all works as it should.

So would I have any problems using these pins even though it is CAN bus??

Thanks Jay


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## Spandex (Feb 20, 2009)

jayTTapp said:


> So would I have any problems using these pins even though it is CAN bus??


I don't see why you'd have a problem. Everyone posting on here who has tried to install an aftermarket HU has had to run an ACC feed from the fusebox or bus bar, so I'm not sure why yours is different, but if it works, don't knock it...


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## jayTTapp (Dec 9, 2008)

Spandex said:


> jayTTapp said:
> 
> 
> > So would I have any problems using these pins even though it is CAN bus??
> ...


All wired in and working well as it should. 

I agree with you Spandex, don't knock it if it works. But, also as you mentioned I seemed to be going against what it seemed everyone else had found. It was the fact that I was doing something different worried me. I just wanted to be sure that there was no reason why I coundn't use the switched live pins from the back of the head unit.

Guys, thanks for your help on this one.

Jay


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## thetomme (Dec 31, 2009)

Spandex said:


> jayTTapp said:
> 
> 
> > So can I use of of those switched live pins??
> ...


Jay,

Were you having a problem with the device not powering up? i have the same issue with my IO Talk, doesn't seem to have power so isn't producing a Bluetooth signal, confusing as the live and earth you described is bridging between the kit and the head unit but the head unit powers with no problem......

looking online i might need a cable??
http://www.nexxia.co.uk/product.asp?product_code=SOT-088&category=iO_Products&section=Car Audio


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## jayTTapp (Dec 9, 2008)

thetomme said:


> Spandex said:
> 
> 
> > jayTTapp said:
> ...


Yes I was.

I was having issues when only using a perm live and negative. However once I also added a switched live, so 3 cables in total it then worked. I assume the internal wiring required the 2 live supplies for it to work.

I'm not sure if you will require that cable adapter, if you get the three right above you only the need to tap into one set of the speakers either front or rear and there you go.

Jay


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## thetomme (Dec 31, 2009)

Cheers Jay,

How did you get a 3rd cable to the switched power? im using the two described in your attachment, do i need to just add a 3rd cable attached from one of those standard ones ie the perm live?


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## jayTTapp (Dec 9, 2008)

Does your IO talk kit require a perm live, switched live and earth??

The parrott kit required all three, I tested my wiring with only a perm live and earth, and that didn't work.

I got success when I connected up a switched live, in addition to the perm live and earth, 3 in total (then your speakers in addition to these).

It was a year ago so memory not so great but you should be able to follow this thread and pictures - I may have some more pictures to help you out.

Jay


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## thetomme (Dec 31, 2009)

jayTTapp said:


> Does your IO talk kit require a perm live, switched live and earth??
> 
> The parrott kit required all three, I tested my wiring with only a perm live and earth, and that didn't work.
> 
> ...


Thats the problem, i think it might need all three but im guessing :-|

the box sits in the middle of the ISO cable from car and headunit, the headunit powers up, and the box uses the same live and earth cable but doesnt. im thinking of just adding a cable from the switched wire loom that you marked on your attachment and adding it the live going into the device? did your parrott have 3 cables comming out of it as standard or did you add one for the switch?

cheers


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## thetomme (Dec 31, 2009)

Ok so here is the update for powering up a IO Talk (or Parrott) on a Half Amplified sound system

From: Andy Horton
Sent: 14 July 2010 17:15
Subject: RE: iO Sales Enquiry

Hi,

It looks to me that there are a couple of things that need to be done in order to get the kit to work.

1)	There is no 12v ignition feed on the radio, so the IO's ignition feed wire would need to be taken to a separate feed, ie cig lighter loom. (The RED is 12 volt battery (U+ plug 1 ) Yellow is ignition. Cut the yellow wire just after the fuse and before it reaches the ISO power plug. Extend this wire to a suitable ignition source)

2)	The telephone mute lead (brown wire) will need to be connected to plug 4 on the TEL MUTE pin.

That should hopefully sort out the problems.

Regards


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## jayTTapp (Dec 9, 2008)

I didn't add any extra wire to the parrot kit.

I think the reply you got is indeed the fix you need an ignition live supply. Yes I did think about taking mine from the cig lighter. However once I have brought myself a multimeter and tested a few of the pins I did find an iginition live going to the headunit. However if you read through this post you will see that other people on here with vastly more experience said there wasn't one. It was going against what people had said concerned me. However my kit has worked without fault for the past 12 months.

Jay


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## fishface (Nov 25, 2006)

jayTTapp said:


> I didn't add any extra wire to the parrot kit.
> 
> I think the reply you got is indeed the fix you need an ignition live supply. Yes I did think about taking mine from the cig lighter. However once I have brought myself a multimeter and tested a few of the pins *I did find an iginition live going to the headunit*. However if you read through this post you will see that other people on here with vastly more experience said there wasn't one. It was going against what people had said concerned me. However my kit has worked without fault for the past 12 months.
> 
> Jay


Not quite true there is not an ignition switched live going to the HU, the HU emulates a switched live (for powering up the active rear speaker), it uses the permanant live switched on by the CAN signal to the switched + terminal :wink:


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## jayTTapp (Dec 9, 2008)

Just found some better pictures I had....these make it a bit clearer.

This is my headunit I have









Headunit wiring sticker









Pin out configuration









Just double check before connecting anything, multimeter is the best thing, I sure I used pin 17, on multiconnector 1 (20 pins connector).

Jay


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## thetomme (Dec 31, 2009)

jayTTapp said:


> Just found some better pictures I had....these make it a bit clearer.
> 
> Jay


Hi Jay,

Thanks for your help on this, the unit is now working perfectly!

Yep as you and the tech guy from IO explained, the switched live doesn't exist on the ISO loom and is on the other car loom for the amp (connection 17)

I simply cut the switched live from the IO cable (yellow) and fed that into that port (also yellow)

Cheers mate!


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## nedge2k (May 4, 2014)

I know this is a very old topic but have just been installing a Parrot Asteroid Tablet kit in the other half's TT...

In my Allroad, I used pin 6 (Bose amp power signal) with my Parrot MKi9200 kit and it's worked fine for over a year.

In her '04 TT, pin 6 goes to 0v as soon as I connected the kit - I don't know if the Tablet has increased current draw (why? it's just a signal surely?) over the Mki or if it's because my A6 has the concert head unit and hers has the Chorus but either way, pin 6 wasn't suitable.

Will try pin 17 tonight and see if it's any better. (if i don't update, it's worked  ) If that doesn't work, I'll try a relay on it and the bus bar.

The bonus of using these pins is that, as the head unit will power up without keys/ignition, so will the BT kit. Oh and the kit will automatically power up with the head unit off and the ignition on - I assume the head unit get put into some kind of standby mode with ignition on.


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