Well the fan works fine now, replaced the final stage unit. However....when I shut the car off I notice a buzzing or humming noise after the key is removed coming from under the dash. Stays on, period. I am suspecting maybe the reason the FSU failed maybe...or may be no big deal. Regardless I have traced the fuse to #31, which is one of SEVERAL fuses listed for heater and a/c...dam BMW book is not plain on what this fuse actually DOES. I notice that if I unplug it and plug it in again the noise stops. Until the fan is operated again and car shuts off. the noise is NOT coming from the engine compartment...any thoughts on this before I put it back together again?