I have a 2001 330xi. Sometimes my fans will oscillate (blow hard, weak, hard, weak, etc.) for short durations. Seems to occur at random times. This also occurs with the headlights and cabin lights so it seems to be an electrical issue. Is there a likely candidate that is the problem? Perhaps the alternator? Forgive me if the question seems silly. I've not a great deal of knowledge about engine mechanics.
The fan issue is likey caused by the blower motor final stage. This is very common and easy to fix. Fix it before it causes a key off battery drain that leaves you stranded (it can run the fan with the car parked.) Headlights and cabin lights is likely a different issue, possibly alternator. You need to have that checked out.
