# Aircon help and advice needed



## TT_hunter (Nov 4, 2010)

Hi,

I am still without aircon on my MK1 TT 180T Quattro (2000 model), despite having done the following:

1. Havingthe aircon compressor replaced
2. Replacing the G65 pressure switch myself
3. Checking the three 30-amp green fuses in the fusebox on top of the battery (which were all fine with clean contacts) and repeatedly removing and replacing them to ensure good contact
4. Checking the 25 amp fuse (fine) and repeatedly removing and replacing that
5. Checking fuse 16 and repeatedly remving and replacing that
6. Removing the entire battery tray searching in vain for a mythical "other fuse box" under there, that someone mentioned on the forum
7. Checking that the small and large fans kick in and drop out on queue

No VAG-COM codes to indicate an issue either (except 15.4 - "sporadic short on the airflow flap potentiometer" )

Please, someone, advise what could be the problem? The clutch on the A/C compressor just doesn't spin.


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## glslang (Dec 5, 2009)

TT_hunter said:


> Please, someone, advise what could be the problem? The clutch on the A/C compressor just doesn't spin.


This is probably really thick but couldn't be the clutch that is broken?


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## TT_hunter (Nov 4, 2010)

Good question, but I'm almost 100% sure no.

The compressor on the car is a brand new one, fitted as a replacement when Awesome GT in Manchester advised it was the compressor that was at fault for my aircon not working (still a bit fed up about that).

The original compressor is sitting in my house in a box, confirmed fully working by the garage I instructed to take it out.

The odds of having two compressors, one that's new and the other with a clutch that works fine when given a 12v feed directly, seem pretty slim to me. I'd guess it has to be a broken wiring connection somewhere.

However, finding what connects to what on the aircon is a nightmare. I've read the section in Bentley's on A/C from end to end and searched all over the internet, and I'm still no clearer which wiring feeds where (the diagrams in Bentleys are wrong anyway, as the G65 was shown in a completely different place than where mine is, which doesn't fill me with confidence about any other advice they offered).

I don't have the skill to dismantle the entire engine to trace the wires. Wish I had a simple explanation or diagram of all the key parts including electrics and what feeds to what.


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## Tritium (Apr 25, 2011)

Maybe you should just swallow hard and take the car to a vehicle air con specialist. Or, dare I suggest a stealer [smiley=bigcry.gif]


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## TT_hunter (Nov 4, 2010)

Ouch!

[smiley=bigcry.gif] [smiley=bigcry.gif] [smiley=bigcry.gif]

I've already had the car to an auto-electrician, who had the car all day and couldn't find an electrical fault (but didn't charge me for his work, so RESPECT to him); and had the car to the "stealers" once, who had it for an hour, charged me £100 and told me what I told them when I took it in!

And Awesome's advice set me back £300 and didn't ultimately sort the problem, either.

(I take your point, Tritium; just feels like it's money well spent only when the issue is FIXED at the end of it)!


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## Typhhon (Oct 28, 2006)

Go to Waks page and download the TT Self Study Guide. It has a layout guide for the system.

I think your problem may be fan controller that drives the N25 compressor clutch relay.

If you can 'hot wire' the compressor then it suggests no power from the controller?

Oh and also check the pressure switch is not 'open' circuit.


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## bobbobb (Dec 24, 2008)

i know this might sound stupid but have you made sure it has plenty or R134a in?


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## Typhhon (Oct 28, 2006)

If you don't have gauge set then check the LP switch. It can be hot wired as well (watch cause some models have a compound switch).

Vehicles equipped with A/C pressure switch -F129-: -V7- comes on and runs at speed 1
Vehicles equipped with high pressure switch -G65- and Coolant Fan Control (FC) Module -
J293- version "1": -V7- comes on and runs at speed 1, NOTE THIS! regardless of initial refrigerant system pressure.

Vehicles equipped with high pressure switch -G65- and Coolant Fan Control (FC) Module -
J293- version "2": -V7- comes on and runs at speed 1 after refrigerant system pressure has
reached 12 bar.


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## Typhhon (Oct 28, 2006)

Would be really interested in your solution.
Putting an article together for the TTOC mag.


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## Typhhon (Oct 28, 2006)

http://130.74.178.25:85/newsletter/ac/a ... ontrol.pdf

Note it for the USA models but might help....


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## qemboad (Mar 4, 2012)

Hi,

Some years back I also had problem with the aircond after having it replaced after an accident, the symptoms was that the aircond worked five minutes initially, but after the engine got worm it shutdown.
After a lot of troubleshooting it turned out that the wiring schematics was wrong on my production series, there was sensor in real life that was not supposed to be mounted until on the next series.
And that sensor was faulty, I´ve not memory of the name of that sensor, but it gives you a lead.

My TT is produced in okt 99.

/BoA


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## HIRAM (Feb 15, 2010)

> "No VAG-COM codes to indicate an issue either (except 15.4 - "sporadic short on the airflow flap potentiometer"





> ------------------------------------------------------------------------------
> Address 08: Auto HVAC Labels: None
> Part No: 8N0 820 043 A
> Component: TT-KLIMAVOLLAUTOMAT D03
> ...


I had the above problem with my TT the battery would drain over night plus no aircon. took me 5 months to pinpoint it without the aid of any wiring diagrams etc, so I'm only to happy to pass my "hands on" experience. First of all I used VCDS 908 (VAG COM) to get the above results. I could clear the code and re-scan and no fault would show but when I did a "functions output test" the fault would reappear. I bought a Potentiometer Positioning Motor for Air Flow Flap second hand from Germany and eventually it arrived, fitted but same problem spent the next few months covering old ground no one on here had a clue and either did anyone else in other forums. After dismantling most of the electrics as per photo, I bit the bullet and bought a brand new Potentiometer Positioning Motor for Air Flow Flap which was about £110. This fixed the battery drain and my aircon began to work but I did as you have done and replaced alot of other things first so could a combination of more than one thing but definitely the battery drain was due to this "Potentiometer Positioning Motor for Air Flow Flap"

ROB

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## TT_hunter (Nov 4, 2010)

Hi HIRAM

Jsut read your response on my post. So, where does the air flow flap potentiometer positioning motor live, what does it look like, and how do I remove and fit it? Any ideas - could you maybe point me in the direction of the right pages in the Bentley's guide if it's there, or suitable online reference detils?

I'm surprised, given how fiddly and weird some of the stuff on the TT is, how hard it is to find visual reference material to support any written procedures for fixing bits on the car. Even Bentley's isn't that clear or co-ordinated int he details they provide.


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## TT_hunter (Nov 4, 2010)

Also worth adding that I have now replaced the fan controller module with a brand new unit - no joy.


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## Tritium (Apr 25, 2011)

TT_hunter said:


> where does the air flow flap potentiometer positioning motor live, what does it look like, and how do I remove and fit it? Any ideas - could you maybe point me in the direction of the right pages in the Bentley's guide if it's there












Number 3 in the above image is the flap motor and potentiometer. 
See Bentley manual section 87-10

Brian


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## HIRAM (Feb 15, 2010)

This is the air flow flap potentiometer positioning motor what causes the G113 error. The Bentley illustration of heating and air-con is for a left hand drive, as shown in a previous post and this part is the number 3 in that illustration. You have to remove the Glove Box to gain access to it and its very very very tight squeeze to get into it but it can be done, as I have done it, maybe someone with petite hands would be able to get to it easier. It's either that or remove the heater air-con assembly,that's a major,major job I dont know if would fix your problem but as previous mentioned this was the cause of my fault codes and battery drain.... There's always someone who knows better than me. I only give advice on my hands on practical experience. fingers crossed for you

Rob


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## Typhhon (Oct 28, 2006)

If you remove the pollen filter you should be able to see the flap operating (or not as the case may be)


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## HIRAM (Feb 15, 2010)

I totally agree with what Typhhon says, but it can still go through its operation cycle and give the fault codes. The "Black semi-circle" in the picture above is split into sectors and the big white cog has small wire "hairs" that comes from it to make an electrical contact, much like the contact brushes on a Scalectrix car. If one of these "hairs" becomes worn or becomes faulty for what ever reason or touch another one then VCDS will register it as faulty. This unit is such a primitive attempt at technology.


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## TT_hunter (Nov 4, 2010)

HIRAM, just read your last reply about the potentiometer. Cheers, and to tohers who contributed too. You guys really are the best - thanks for the responses, my plan is to replace the potentiometer; then if still no joy I will surrender to the stealers I reckon.

At least, if they suggest replacing the potentiometer, hi pressure switch, compressor/clutch, battery compartment fuses, fan controller module, fuses in the fuse box, re-gassing the system, or anything else listed as a 'stopping point' in their diagnostic (i.e an unnecessary job to cost me money), I can say "DONE, DONE, DONE, DONE DONE DONE.... now can you just please find what's wrong!!!!!!" [smiley=argue.gif]


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## TT_hunter (Nov 4, 2010)

Right that settles it.

I had a chat with my Quattro, via the VAG-COM. Also stripped out the glove box and got my hand in there (thanks for that tip). I can hear the air flow flap motor reach the limit then keep clicking for a while trying to move on. Plus the VAG-COM shows an error for the part - "30.00 short to open or plus".

I'm keen to get the right bit before I rip the existing one out - can I just confirm that the pictured part IS the one I need (it carries the ref 1J2 907 115A on it, I noted). When I look up unit "V71" on the 'net for parts, people are selling various similar items that don't look like these pictures.


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## HIRAM (Feb 15, 2010)

Hi
The part number of my V71 is "1J2 907* 511A*" and not " 1J2 907 *115A*"..... but in all fairness the photo I put on the post is upside down ..so my fault :roll:

I recommend fitting a new one as I have mentioned before I got one from Germany and that turned out have the same fault but you pays your money and you makes your choice.

One thing I will say is this part is a VW part well that's what the "1j2" would suggest, so if you go for a previous used one it dosn't have to come from a TT as long as the part number matches or there is a supersedure to that part number it should do the job. If you do go for a new one get a price from VW and SKODA etc. dealers and one from Audi stealers, the price can vary for the same part from each other. I also believe there are aftermarket companies who also manufacture this part but I dont know this for sure.

Hope this helps

Best Regards

Rob


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## TT_hunter (Nov 4, 2010)

Cheers Rob, I put my order in (minus the typo) for a new unit. Fingers crossed.


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## HIRAM (Feb 15, 2010)

The stress and frustration of this must be driving you COCO LOCO, truly hope this is it this time. The clicking, sounds like the V71 is not registering that the lever has completed operational cycle. Fingers crossed

Rob


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## TT_hunter (Nov 4, 2010)

Hi. Back again.

The TT is with the local dealer now. They are dumbfounded (Audi Technical can't sort the issue either, apparently). When they directly feed power to the new a/c compressor all works fine, but no signal is being sent to the compressor. They swore that replacing the a/c control unit would sort it so I agreed to that. £1200 later and still not working. They've added £2k of their own work too and loaned me a new TT free, until they sort my car!

They now say the Revo re-map I had done by Awesome GTi could be the issue (as I now have apparently a 'non-standard' ECU on the car). I am inclined to disagree, as I'd had no working aircon for a year before I took it to Awesome for diagnosis - I only had it re-mapped by them 'cause it was already there with them!

(as a brief reminder, I have a new pressure sensor on, new fan control module, new airflow flap potentiometer, new a/c compressor, new a/c control unit, wiring all apparently good, all fuses and battery-box connectors OK)

Someone suggested that a non-standard radio could cause aircon issues (I got a Navsure fitted by Halfords a week after I bought the car, to replace the Audi Concert 1 radio cassette) - could this be relevant?

Please, any advice is welcome to avoid a further bill to replace the ECU (which might be needless).


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## Typhhon (Oct 28, 2006)

Unless they can prove me wrong ....The dash climate control unit drives the A/C ...... the main ECU should have no impact on its ability to run as long as it has power.....

Suggest they read their own Self Study 207 booklet.

And I think loads of people have non standard radios....and working A/C....


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## Typhhon (Oct 28, 2006)

The system can be checked at the controller with the VAG tester to ensure all inputs and outputs...

Here's the first few images from the procedure...





































Just had a look at the wiring diagrams and it seems if your controller display works and your blower works you have power for the A/C... that should shove the ECU remap? :?

Lots of diagrams however......


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## TT_hunter (Nov 4, 2010)

Thanks Typhhon. They didn't press for replacement ECU today - however I did loan them my Bentleys manual as they didn't have a wiring diagram for my 2000 model car any more (?!!!).

The non-technical explanation they've given so far is that as far as the control unit is aware the engine is off (borne out by page 78 of 207 guide which lists the auxiliary signals, including road speed signal, Engine speed signal and Engine temperature/engine hot LED - if only I knew how those signals are being sent and by what means maybe that would explain what's wrong?)

The procedure you showed extracts of - what is its technical title? Where could I get hold of a copy online that I can forward on to them?


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## Typhhon (Oct 28, 2006)

This is all from ElsaWin the VAG group service data...

About £6 on ebay

Also has all the wiring diagrams...

I will try and copy the electrical signal list for each connector later today...frankly if I can get this data a 'proper' garage should have it.....no?


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## Typhhon (Oct 28, 2006)

I think these are the relevant ones.

The VAG multitester is basically a multimeter your looking for resistance and volts...

If you need a specific page or table drop me a line....


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## TT_hunter (Nov 4, 2010)

Great, Typhhon, thanks mate. As for your earlier comment, I would have agreed they should know this stuff (which was the point of taking it there and swallowing the £100-an-hour labour rates), but I've added the caveat to them that I'm not trying to show off or insult their knowledge or skill; I just want my car fixed so I'll try anything or do anything to get there).

I'll pass on the images by email to the Service team in case they don't have it or it just prompts another line of enquiry that gets everything working. Cheers again - this is why I got the TT; because it provokes love and obsession from a good crew of people!


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## Typhhon (Oct 28, 2006)

PM sent


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## TT_hunter (Nov 4, 2010)

Defo. Yes please - (can't PM until I post more)


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## alf1956 (Jul 29, 2010)

qemboad said:


> Hi,
> 
> Some years back I also had problem with the aircond after having it replaced after an accident, the symptoms was that the aircond worked five minutes initially, but after the engine got worm it shutdown.
> After a lot of troubleshooting it turned out that the wiring schematics was wrong on my production series, there was sensor in real life that was not supposed to be mounted until on the next series.
> ...


i have exactly the same problem with my 1999 tt! example:today i started up my tt&put the air con on&it blows very cold air then after 7 mins the air con compressor just stops&we go back to warm air.i have had this problem for 2 years&tried everything but to no avail.i can diret feed the comp from the battery&it works perfect.if you check my posts you will see what i have tried,it has proper done my head in as my tt is in portugal where you NEED the air con so its not as though i can take it anywhere except the stealers which i did for an idea of what they thought it was which they told me they thought it was the compressor at €1,000 i though no way !!i wasnt going to shell out all that cash on a thought !!


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## Typhhon (Oct 28, 2006)

TT_hunter said:


> Defo. Yes please - (can't PM until I post more)


 Done!
Do read the instructions..... carefully....


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## Typhhon (Oct 28, 2006)

Any progress??


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## merlin c (Jan 25, 2012)

Looks like you've done part of this test but try the other part part of this test that tests the compressor clutch engagement solenoid.





























part of this test but here is also the compressor clutch engagement test.


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## Typhhon (Oct 28, 2006)

So any success .....


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## TT_hunter (Nov 4, 2010)

Aircon fixed. It turns out that the owner before me must have replaced the ECU and it wasn't sending engine revs so the a/c control unit thought the engine was switched off. Very expensive sorting it out at £2.2k for all the diagnosis, a totally unnecessary replacement of the control unit and the replacement of the chipped ECU with a standard one. Was it worth it? Well, if I didn't now have a problem with the wipers I'd know everything was fine with the car. Almost there...


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## HIRAM (Feb 15, 2010)

*Wow*,I would have never of guessed that one [smiley=book2.gif] . I wouldn't be surprised if you were the only person in the world that has ever had that fault. I would like to say a sincere thanks for completing the post and telling us the final out come as so many posts on here do not conclude. Hope that you have trouble free time now

Rob


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## Typhhon (Oct 28, 2006)

Duh! I think Audi are having a laugh not being able to get that data quickly.....
Thanks for the feedback anyway
Hope the ElsaWIn helps you save a bit next time!
Least you can use it for demist now..... :?


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## audi42 (Oct 28, 2013)

Did you know that there is software that controls the climate control systems in Audis. I went thru many of the same puzzling things that all of you encountered with no resolution (had my 2004 Audi A6 to the dealer 3 times for diagnosis).
Finally, one of the techs at the dealership suggested they set all of the climate control settings back to their "Default" settings and suddenly the A/C started working.
Not sure if this holds for older Audi models but I will soon find out as the A/C in my 2000 TT Quattro stopped working (I found the front of the A/C clutch assembly on the ground in my driveway). The A/C made a grinding noise a few time when I turned it on & then this piece fell off.
It looks like it was splined to fit over the compressor shaft but the splines are gone (probably a jammed-up compressor).


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## MCIP (Aug 16, 2014)

Just payed out £540 for a brand new compressor all fitted by Air con shop in tipton west mids he said it was hell of a job to do n would charge more if he done another (v6 model) Nice n cold now so hope we have some more nice weather.


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