I checked Bentley. I was referring to the mechanic fan (the fan between radiator and engine), not the aux fan. Sorry for the confusion.

But how come the mechanic fan always on? In my old car (an Acura Integra), the fan only comes on when the engine is hot. And it stays on after ignition is off if the engine is still hot. The e34 mechanic fan seems like "attached" to the ignition regardless of the engine temp. ???