zakiu

Hey guys, I just bought an '01 A4. It's a 1.8T Automatic Quattro.

When I started it this weekend, the battery had died so I had to jump start it.

After I jumped it, The HVAC was blowing cold air even on HI heat. I tried AUTO, manual modes, etc. and nothing worked. Then I noticed that the gauge cluster was showing an external temperature of 23 degrees when it was really 50 degrees outside.

I restarted the car (lol like a computer), and the external temp was 59 degrees and the HVAC wouldn't blow any air at all when on Auto mode at HI temperature. The external temp slowly dropped back to 23 degrees and as it dropped, the HVAC started to come on, but was blowing strictly hot air.

I'm new to Audis and have always been an M Car owner. I know on certain BMWs, HVAC problems are common. Does anyone know if this is a common problem or an easy fix? I don't have my tools or any diagnostic equipment handy and would really like to avoid taking it to the dealer / indy shop if this is a common problem.

I'm in Atlanta. Thanks!

zakiu

Also, it has 104k miles and has had a lot of recent work. Not sure if that matters.

In the last 20k miles,

New Tires, Front Brakes/Rotors, Rear Brakes/Rotors, Expansion Tank, Timing Belt, Waterpump, Thermostat, Coolant flange. Engine Mounts, Camshaft/Output Shaft Seals Camshaft Adjuster Solenoid, Cam Sensor, Valve Cover Gasket, Spark plugs, Right Axle Boot.

Also just had the sunroof drains clogged a couple of months ago. The water leak had damaged the Transission Control Unit and ECU Relay, so both were replaced.

M3Armand

Try backflushing the heater core. This has worked for my car and I have 293k miles... Do a search here and you'll find out how to do it. Search is your friend.

zakiu

thanks. shop diagnosed it as one of the two external temperature sensors and has nothing to do with the heater core. apparently this is a well known common problem.

M.S.G.

Just ran into the same problem myself.