HELP - no air con

[herby0001]

Hi,
I am looking for some guidance regarding my air con on my 2006 Audi A3 2.0 TDI Sportback, 8P.
A few weeks ago I noticed that the air con was no longer giving out cold air. There is no clunk that you would normally get when the compressor kicks in and the separate fan on the rad for the air con does not kick in, though it spins freely.


Along with a very nice and helpful local garage, the following has been done so far:
1. Checked, tested, cleaned and re-seated several fuses next to the driver's door - the ones that say they're related to air con. Fuses checked in engine bay.
2. Scanned for codes using garage kit (possibly Snap On). There was a code 01320 which related to the air con controller, so I bought a 2nd hand replacement from eBay. Cleared all stored codes, still no air con. Code 01320 did not return though.
3. The air con gas has been checked - the correct amount was in there, no leaks.
4. No HVAC codes stored (except for the usual aux heater)
5. The compressor was replaced about 3 years ago.


Could it be down to a relay? I cannot seem to find any information anywhere about the Audi A3 8P having an air con relay.
If the compressor has failed (again!), would that definitely be giving a code? Same for pressure sensors?


With no codes getting thrown, it would seem to be something simple, but we are running out of ideas. Grateful for any pointers!

[Crasher]

The compressor never would have "Kicked in", they are a constant drive variable displacement unit with no magnetic clutch. Which controller was the code in?

01320 - Control Module for Climatronic (J255) - No Signal/Communication

This would normally be stored in the central electrics unit address 09 along with

00256 - A/C Pressure/Temperature Sensor (G395) - No Signal/Communication

And in the engine address 01

4708 (U0164) - No Communications with HVAC Control Module (J301)

And no communications with the HVAC unit at address 08 but the Snap Off kit is notoriously crap at VAG stuff and misses a lot of none P code faults.

[herby0001]

Hi Crasher,
Thanks for your reply. I was told by the mechanic that the 01320 code related to the Climatronic unit in the car, so for £30 it was worth a try. I bought a secondhand unit which seemed to resolve the 01320 code. No other relevant codes remain, that the kit can see at any rate.

So (please humour me with my simpleton logic!) when you say the compressor is constant drive with no magnetic clutch, does that mean that the compressor runs whenever the engine is running with no electrical components like a relay to switch it on and off? Is it a simple matter of saying that the compressor runs all the time and if it isn't, then it's is knackered and needs replacing?

Thank you!

[Crasher]

The pulley runs all the time driving the internals, should they seize the pulley has a shear coupling which, shears, but keeps the belt drive running. These delivery of the compressor is controlled by a frequency valve in the side of the compressor call the N280, this is modulated by the control head using the pressure sender values.

[m8gic]

Did you get to the bottom of thi n the end?

I think it may be the Pressure switch

[herby0001]

Hi, sorry for not replying to this thread sooner.
There was a lot of head scratching by the garage. They were adamant that the compressor was not at fault so they were going down the routes of wiring fault, relay & fuses. The car was in the garage repeatedly, 1-2 days at a time, each time coming out with the a/c not working and the garage saying they needed more time. It felt like this problem was being looked at only when there was time at the garage to fit it in around their other work and this wasn't very high in their list of priorities. I had a lot of faith in the garage from previous work but this was starting to drag out too much. I got a loan car in the end which, maybe coincidentally, added some focus - they took the compressor out to test and then were able to confirm the compressor was shot. Compressor replaced, lovely and chilly again. They were really the compressor failed as soon as it did - looking at receipts, it was almost exactly 4 years old.