i just recently bought a '98 3.8 m5, and the heater control is stuck on the feet and defrost. the **** it self isn't stuck but the ducting is stuck open on the feet and defrost.

also, shortly after i bought the '98, my '94 3.4 a4 had the same problem occur with out warning.

does anybody know where this problem is comming from? what keeps the ducting stuck on this?

 

[&:] the controls for the selector are vacuum operated so this is where id start looking. there should be a black hard plastic line and a one way valve from the intake to the fire wall above the heater box in the engine compartment. this also tees off and goes to a vacuum chamber. check all the lines fittings and especially the tee/ one way valve let us know what you find kurt