Markgcb1

Hi I'm new to the forum. I have a 2002 Audi TT Turbo Quattro. This past weekend it was very hot. I was running the AC fine for about an hour, stopped someplace came back to the car and then the AC started blowing warm air instead of cool air. The next day I started the car and it was still blowing warm air. I looked at the temperature reading on the dash and it was a little to the right like right past the mid mark. I drove around the corner and the cold air started blowing out again. After this the AC worked fine for two days. Now today, I start the car and cold air is blowing fine. I'm driving on the highway, cold air is fine. Then I come to a stop all of a sudden the warm air starts blowing out again, and the temp guage starts moving a little to the right like a notch or two past the mid mark. By the time I get home and let the car idle, the temp gauge moves all the way to the right stating that the car is overheating or too hot, but no smell of ani-freeze, no smoke, and AC still blowing warm air. Does this sound like a thermostat issue? If not, can anyone tell me what it may be and what I should expect to pay to have it repaired at the dealer?

Rocky-in-Connecticut

however, this module is expensive compared to a AC high pressure switch or a thermal fan switch (in the radiator). If the fan control module is shot then your electric radiator fan and your ac compressor will not kick on

DasTT

check in order... thermostat, temp sender, fan control

You'll likely find that one of those at fault. The result of which is the AC controller will not run the compressor because engine temp is not acceptable.

Then go for the AC side of the equation if all the above are OK.

TTinCT

a blend from inside and outside air. If you set the recirculate button to on, it will keep the air a bit colder.

To check to see if the car is running warm, push the recirculation and up arrow vent together. This will put you into diag mode. use the temp control **** and select block 49c and push the recirc button again. This will tell you what the temp of the car is...
Anything over 114c and the ac shut's off to prevent overheating....

I would start with that before i determine if anything is actually wrong...IMO.

Markgcb1

Thanks for your help. If it is the thermostat? temp sender? or fan control? Do you know what the dealer would possile charge for this?

Markgcb1

Thanks. When you say expensive, approximately how much will I be looking at if this is the problem and I let the dealer repair it?

DasTT

I just get parts, so have no idea what they would charge for the diagnostic and labor.

Markgcb1

Thanks for your help. I really appreciated it. I did axactly what you said and it worked. The temperature was about 97C and then it went down to 95C and varied between 95C and 96C. The air starting blowing cold again. When I first went out side and got in the car I turned the AC on and it was still blowing warm air, but the temp gauge stayed in the middle and did not move to the right to overheat. I drove it without the AC pushed on for about 12 minutes and then pulled over to let it idle and it still did not overheat. I turned the AC on after that and it started blowing cold air again. Is this normal? I've had the car for about 8 months, it has 60K miles on it. I had the 60K maintanence done about two months ago and have never had this problem. So give me your thoughts on this issue? The temperature outside earlier today was about 100 degress with the humidity it felt like probably 115. Are these cars known to do this when driven in excessive or "heat wave" temperatures?

TTinCT

i will tell you at idle with just the Auto setting on, you can get a bit of warm air. Once the car is above idle at speed or not, the temps drop. Drive the car for a few days with these settings. If it does not go over 114deg, you are fine.

Try turning the recirculation button on...it may alleviate some of this...but not all. It sounds fairly normal to me....but i guess it depends on how warm "warm" is....

Silvr_Surfr

a bum A/C compressor. The temp. guage was bogus also so they replaced the cluster as well. Don't mean to scare you but thought I would offer my experience. You got some great advice above, I hope it's something minor.