Air Con problem on S3 (2000 plate).

[lloydsta101]

Hi all,

Since we've been having a bit of hot weather recently, I thought I would invest in having my Air Con re-charged. It's my third car with Air Con now, yet they've always needed re-charging when I buy them and I've never bothered before.

Anyway, I booked it in to a local garage yesterday who charged £45 to have the system checked and gassed. They said there were no leaks or problems and the compressor (or whatever he called it) was working fine. Although upon switching the system on... nothing! The blowers are still going exactly as before, but there is no change in temperature. The little frost symbol is showing down in the bottom left corner and I have it set to 'LO' on the display.

Is there anything else that I can check that may cause the system to not work? He did mention a pressure switch or something along those lines, could that be the cause or is it more likely to be something simple like wiring/fuses?

Any ideas would be a great help to me, thanks!

 

[jojo]

So you've taken it to an Aircon specialist(I presume) who could regass it and give you the diagnoses that everything is fine, but doesn't have an answer as to why it's not blowing cold air?

I would personally ask for my money back and take it elsewhere mate.

 

[lloydsta101]

Hi, thanks for your reply...

Well the place I took it is only a MOT and Service Centre/Bodywork Repair garage (only as my mate works there and it's on the same estate as where I work), but they don't actually do the Air Con re-charge themselves. They call a company called Sparks Auto Electrical in to do it and they were the ones that gave this analysis.

I did think it was a bit odd that they could tell me what wasn't wrong with it, but couldn't tell me what was. Their advice was to check the pressure switch and should they need to take out the gas (for some reason), they will draw it out and re-gas it free of charge.

 

[darkfibre]

Funny you should mention all this, I had exactly the same problem till about 20 mins ago on my S3 - I had two exposed wires leading back to the compressor. Had these patched up and now works. Moral of the story...it could be something as simple as that...so get them to check the simple bits before jumping to conclusions...or get your money back!

 

[markymark1984]

Mines been in the garage this week for a similar issue. The driver side rad cooling fan should kick in when you turn the air con on as far as i understand it but nothing happens. They've had a look over all the things that it could possibly be and have come to the conclusion that they need to take the dash and steering coloum off in order to reach some heater box or something like that that controls the air con (same place as flapper valve?). Even then it didn't sound very convincing they'd be able to fix it, plus that would equate to 1.5 days of labour apparently!

These guys aren't audi specialists so i think im going to have to take it to APS and see what those boys think. They seem to be able to fix anything, you just have to be prepared to pay a fair bit of ££!

It looks like the weather is getting warmer again towards the end of the week, i'll be preparing myself for sweaty back syndrome again!

 

[lloydsta101]

Thanks very much for your response. That is what my friend has suggested checking... we're going to have a look at all the wiring before anything else, hopefully mine is as simple as yours was!

 

[AndyMac]

Mine was very simple just a worn out condenser fan (the smaller of the 2 fans on the back of the radiators). This fan should be on all the time the A/C is on, if it isn't then the A/C shuts down. GSF had one in stock for about £80 (B5 A4), so really simple fix. Easy to check as well, if it isn't working simply unplug it and apply 12v directly to it, or check 12v is going to it. If it is then the fans bust.
I made the mistake of getting a specialist VAG garage to look at it as they were just round the corner. They did exactly the same, charged me £35 for a regas and said they'd need more time to investigate at no point finding the fault that was staring them in the face. Took it to an AC specialist and they found the problem within minutes, told me what was needed but I did the work myself and took it back to them to do a proper service on it.
This is a recurring problem, everywhere is claiming to do A/C work (clowns like Kwik Fit) and though they may be able to do a simple regas have no expertise beyond that so you end up paying twice. A regas is really only needed when the A/C is working fine just not as cold as it should be. If it isn't working at all then a regas will not cure the problem.

 

[myke]

there is a bolt on the compressor that connects to the clutch , no problems will show up in vagcom but the bolt costs £2.50 or if you find it onthe floorpan loctite it back on ;o)

 

[madsad1]

had same problem took to kwik fit said problems doing any audis . got it gassed no difference took it home pulled out a/c fuse and any others fuses to do with fan or cooling and hey presto now ice cold .give it a try cost you nothing?????????

 

[thegoal007]

had same problem took to kwik fit said problems doing any audis . got it gassed no difference took it home pulled out a/c fuse and any others fuses to do with fan or cooling and hey presto now ice cold .give it a try cost you nothing?????????

what ?????????? Your running a/c without any fuses !!!!!!!!!

 

[lloydsta101]

Well, I've had my mate take a look at it! First of all he stuck a little device into the wire that powers the compressor and gave it a surge directly from the battery... instantly the Air Con started to get cold, but only while he was holding this button to power it. So he traced the wire back to a Fan Control Unit (Part No. 1J0 919 506 K), situated under the battery and held on with two bolts.

He unscrewed the bolts and unclipped the Fan Control Unit from the bunch of wires that were going to it, then opened up the casing to have a look inside. Basically, what we found is that the two bolts holding it in place had been over-tightened and gone straight through and damaged the circuit board of the unit. The board was split and some of the solder/resistors etc. broken, so it's obviously not giving any power out to the compressor.

So, hopefully... I should be able to just replace this unit, which is fairly simple to get at and put a couple of shorter bolts in to stop it happening again. Anyone ever had to replace one of these before, how much do do think it will cost?

 

[jojo]

Whilst it's all apart, it maybe an opportuniy to take some pics for us to look at and gain some more 8L wisdom. :thumbsup:

 

[lloydsta101]

We threw it all back together straight after finding the fault, as I need to drive it until I can get a replacement unit. I did take one picture though, in case I needed to explain what I wanted to a scrappy or something. The picture shows part of the Fan Control Unit (as it is bolted from above, but sits mostly under a metal plate)... the little device my mate used is pointing to it! Also, the bolts that hold it in place (extremely rusty) are in the picture. I've left one out though so I know what gauge/thread type to look for when finding a shorter replacement.

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[chris_marshall]

Just read this thread out of curiosity, as my a/c has been crap and was about to get it regased, only to find my fan isnt coming on either. Very reliable these cars seem to be lol

 

[madsad1]

what ?????????? Your running a/c without any fuses !!!!!!!!! i think i never explained myself correctly pulled the fuses and then replaced them again and this solved the problem with fan and aircon

 

[madsad1]

sorry never explained pulled out fuses and replaced them again ?????

 

[chris_marshall]

sorry never explained pulled out fuses and replaced them again ?????

Where is this fuse?

 

[lloydsta101]

*** Update ***

Well it seems that my problem may have been the Fan Control Unit as mentioned, as I replaced it today (took about 15-20 mins) and I think it's now working. I only had 2 minutes to test it, but I can now hear the compressor kick in and it seemed fairly cold. Not as cold as it was the other day when my mate gave the compressor a surge of power directly with his little tool, but it was a much hotter day then so I might just be imagining it.

Anyway, I'm going to give it a proper test on the way home from work when it's been running for a bit and has some engine power behind it rather than just idling. I took a picture of the offender in case anyone else gets the same problem and needs to replace it, although mine had been savagely attacked at the core by two extra long bolts: