Have you received any resolution on this? I recently acquired a 2001 530i and twice now I have found the battery dead. I had it in my garage a few days ago and then I heard a fan running. It seems to be the heater fan on very low. I opened the car door to get in and after I sat down it turned off. I exited the car and several minutes later I heard it running again for 1 or two minutes. This happened three times while I was in there. The next morning I started the car and drove it two miles to work. 9 hours later I tried to start it to go home and it would not turn over. Lights very dim. What can cause this fan to run when car is off and no key in ignition. Or could this be the little fan in the bottom of the computer box that I am hearing? What controls this fan