Hello, I'm hoping someone here can help me out. I recently purchased a 2001 Audi A4 2.8l Quattro wagon. The only problem I seem to be having is with the heat. I turn on the heater and only get cold air blowing. The climate control works fine. i checked the inlet/outlet hoses on heater core, they're both very hot. I have no air in the system either, and i checked the fuses which checked out ok. Now is there a possibility that i have a blown relay or something else? Any input on the matter would be extremely helpful. Thank You.

 

It sounds like the Climate Control servo that controls the flap that varies the temperature is not working correctly, or at all. However, it could also just be a dirty (clogged) cabin air temp sensor port. It is usually a small open port (looks like a tiny defroster port about an inch or so square) on the dash somewhere. Most are located on top. These can get dirty and easily blocked off. Take a vacuum cleaner and see if you can suck some air back through it. This might clean it out enough for it to start working again.

 

Great tip Dave! I would do the same