My 2005 Audi A6 (3.2) frequently blows hot air while running the air conditioner. The oddity is the A/C does not blow hot air out all vents, just the side vents. The center vents will stay cool, but I have to close the side vents because it immediately becomes very uncomfortable. This happens nearly every time I drive more than 20-30 minutes. It happens sooner when driving in town with multiple stop/starts, and will delay longer if I drive on the freeway while cruising at a constant speed. I do not drive aggressively, so I do not think it is due to the systems reserving power for engine performance. I have found a temporary fix to be shutting off the car and restarting it. This apparently resets the system and the A/C operates correctly for 20-30minutes, then the hot air problem repeats. This of course is very inconvenient and not a solution I plan to accept indefinitely.

I have had the refrigerant recharged, and I have had my specialty German Auto mechanic attempt to diagnose this problem twice with no success. While reviewing other forums (including other auto makes) I have read discussion of people replacing the Climate Control Module for costs of $1400+, and still not fixing this type of problem. The most successful results have been replacing the evaporator temperature sensor(s). In such cases they “found evap temp sensor was stuck reading one temp and would not fluctuate with temperature demand”. Therefore, I seek advice on this as a solution and/or advice on how to perform the work associated with replacement.

Note: Primepartssuperstore.com sells evaporator temp sensors for “center”, “lower”, and “upper”. Should I plan to replace all three? If so, does anyone have suggestions or details on how to locate/access these parts to replace them? I have read in many cases, this involves removing the entire dashboard assembly. This seems like a troublesome step if I am not sure the evap sensor is the problem. Is there an easier way to check that the temperature sensor is the real problem?

 

This is a known problem with the C6. Audi has issued a TSB setting forth the repair procedure. Send me a PM, with your e-mail address, reference the AC problem with the outer vents blowing hot air while the outer vents blow cold air, and I will e-mail you the TSB.

 

Did you ever resolve this? I am having the exact same problem. I just bought this 2005 with 55k and I am not happy about the thought of a huge bill.

Thanks for any help.

 

I know this is quite an old thread now but I have developed the same problem with my car and wondered if you would be good enough to email me the TSB also

my address is kenney.murray@btinternet.com

 

This must be contagious. I have exactly the same problem. If you get a TSB would you please forward it to larrystemp@comcast.net.

 

Mine does it too....has 160,000 miles on it......whati do is come to a stop sign shut the car off for 30 secs.........and restart it.......blows cold again? I just chalked it up to a ghost in the machine....

 

Here is the link to my entire TSB library. Take a look in the HVAC section for the TSB you guys are looking for. Good luck.

 

Hi did you ever fix this. My Audi is doing the exact same thing as you described below

Enoggin@gmail.com

 

My turn to revive this thread

 

could you please share the TSB library link j have the same problem now