dcashmer

Hello all,
I recently bought a used 2005 A6 Quattro, 3.2 engine if it matters. I bought it know ong that the A/C was an issue. After some searching on the internet, I was guided to AudiWorld and the forums. I've read about the heat control unit sticking and only blowing cold air. And also how to go about fixing the issue.

The dealer I bought it from supposedly recharged the freon before I picked it up.

I'm scheduled to take it in to Audi next week to handle the open recall for the airbag and would like them to check out the car. IO would like to avoid a hefty A/C repair bill.


My question is this. When the car is blowing hot air while the A/C is supposed to be on, is the compressor on or off? I ask this because I see no pools of condensation under my car which would indicate that the compressor is on and functioning.

A6Gary

If you are getting hot air out of the side vents when the temperature is set at a low setting, that is a sign that the heat control valve is sticking. I just replaced that valve on my '06 A6 Avant because I was starting to get the hot air problem. Audi issued a TSB re: this problem, which calls for replacing the valve with a newer part, P/N 4F1-959-617-B (runs $200 for the OE supplier (Jurgen Liebisch) version). Since you checked this forum, then you should know about about to cycle the temperature control from LO to HI to try and unstick the solenoids in the valve.

dcashmer

Hello,
Thank you for your reply. Yes, I know about the heat control unit since I stated exactly that in my post. I also know about cycling the system between Hi and Lo. Tried it. Didnt work for me.

Not trying to be a jerk... But... While I appreciate you taking the time to respond, you simply told me what I already know and mentioned but failed to answer my question regarding the state of the compressor. Maybe the question was just too stupid, since no one else has responded to this thread.

I'll state it again. While the A/C system is asking for cold (settings on LO), but the valves are stuck in a position which provides only hot air, is the compressor on or off? I don't see any puddles of water under my car indicating that the compressor is on and working.

So do I have a valve issue, a compressor issue, or both?

dcashmer

Edited...

A6Gary

If your have the A/C on (i.e., ECON switch off) with the engine running, look at the compressor. If it is rotating, then the compressor's clutch is engaged and the compressor is working. You can also tell by the temperature of the freon lines - the high pressure side will be hot and the low pressure side will be cold when the compressor is running. If the compressor is working, the blowing of hot air is the stuck heater control valve allowing hot coolant into the heater core.

BTW, if you question that your Audi dealer may rip you off, you should take your car somewhere else that you trust.