Frequently Asked Questions - BMW M coupe Interior
What is the interior fan for in the coupe that runs as soon as the engine starts and only shuts off several seconds after the ignition is off?
The fan noise is coming from the cooling fan that is under the computer in the engine compartment on the passenger side next to the fire wall. The fan sucks air from the cabin passenger side, under the dash, and blows it upwards to cool the computer. If you look into this you will find a bellows shaped rubber tube that connects the passenger fire wall with the fan. The fan can be disconnected by opening the computer compartment and you will find a two wire connector on top of the computer that has wires running down to the fan, I'm sure BMW would advise against it. From what I can tell, it's the fan that is causing the noise. Maybe BMW could find a more quitter fan and also look into vibration damping devices.