Hi, i have a 2987 s4 and i have a problem.
Whit the air conditioner in off and the fan at 0, sometimes the fan goes at maximun power for a few seconds.
8 or 9 months ago happend this but now happens again.
Someone knows what happend?
thanks

 

the car is a 1987 928 s4

 

Sounds like some bad/loose switch contacts in the A/C head... probably the system is accidentally getting into defrost mode.

 

This is "magic blower syndrome." Please search for those terms. The fix is a new resistor set for the blower. There's a relay in there that'll come on full if the resistors get too hot. Yours is coming on in error.

 

thanks Glen