I have a 1989 Audi 100 Quattro and the Climate control is giving me fits ! In the morning when I first start the car it comes on and works great for about 30 secounds and then just slows and quits. It don't matter where I set the settings at or how warm it is outside ?

 

I would say that it is probably the flap servo. I tried replacing a bunch of the temp sensors but nothing worked right until I replaced the servo. It’s a very common problem.