AdvNetSol

2004 S4 B6 – changed the battery and now the AC doesn’t work properly. It turns on but blows hot air. I can’t hear the compressor engage either, I’m not sure if it used to make any noise, but I definitely can’t hear anything kick on now. The only other things I have tried is changing the AC fuse and that did nothing. Any ideas or suggestions?

nitro1

Its out of freon. Means there is a leak. I am having mine fixed as we speak. Mine was leaking from the compressor.

mcar11

Not necessarily out of freon; I had the same problem with my 2005, shop told me the freon they measured was not low, and first diagnosis showed ac compressor was defective. If we revved the engine while idle, the compressor would suddenly operate correctly and cold air would flow.

I took it home anyway to see if I could live with it, and there are some days when no cold air will blow, but after revving the engine just once, the compressor would again work correctly and I would get the cold air (it will usually work okay again for a week, then I have to repeat). I eventually will get this fixed, but I'm too cheap right now to do it. This may or may not be your problem, but you can't automatically assume the freon is out. (The shop had measured mine to be 75% full on my '05, and I use the AC a lot).

AdvNetSol

Appriciate it. I haven't had a chance to look at this one. i'll see if i can find a non dealer to look at it (the bakersfield dealer is terrible).

nitro1

If the car is completely out of Freon, A code will appear by the ECON light remaining on.

AdvNetSol

Bakersfield Audi is saying this is a near $3000 job. they claim the AC compressor is not working, and they have to replace it, the dryer and restrictor. i know the dryer should be replaced at the same time, but does that price sound right? seems way too high.

bkrichar

Sounds about right. It's what it cost to fix my 96 A4 about 8 years ago.

nitro1

Yes, that's about right.

Tim in N FL

Wow...$3k!?! I find myself wondering if the A/C compressor failure an epidemic in the 2004 B6 S4? My 12/2003 produced S4 just the expensive shaft-driven A/C compressor (& associated bits) replaced back in May of this year at an independent Audi shop in ATL for $2500 (parts & labor). The compressor was ~$1000 and the rest was labor. Fortunately, it was done just before I bought the car in late June.