A/C climate control issues 2005 A6
 

Help! my A6 climate control has gone crazy. After I've been in the car for 10 minutes or so, one half of the vents will start blowing hot air. Basically, the system runs at half capacity. I end up closing those vents, but the system is clearly messed up. Has this happened to anyone else? My technicians have had a tough time diagnosing the problem. Thanks.

Recharge the gas.

It is a very common problem and well known. Check out the TSB library linked in my signature and look at the TSBs in the HVAC section.

Thanks for the help! I'm taking the car in this week and will share these suggestions with them.

already tried that...not successful

Hey, JW.
Have you recharged the freon gas on your car since you have owned the one?

My car was blowing out hot air from the passanger side vent.
I had looked up the forum and tried kevin's TSB instruction but did not work.
So I brought the car to a technician to diagnos the problem.
He simply said "you are running out of freon gas," and refilled it.
Problem has gone so far.

Its a common problem easily fixed. Valves that control water temp control get stuck and end up blowing hot air from outside vents. Audi dealer changes valves and flushes coolant system for debris. Do a search for "outside vents blowing hot air". If I remember correctly is about a $700 fix.

Ditto same here
 

You CAN do it yourself. The heater control valve is under the plenum cover slightly to the passenger side of center. Several hose clamps and an electrical connection. I paid the dealer to do ours but after looking it over, I should have done it myself and save $400 or so.