I am going through the same issue. Except mine will no longer start at all. However, I now have figured out what is going on. Let me ask you this question: has your car been false alarming at all. Think back a few weeks or a few months even. If so read on!
My 95 740i (186,000mi) falsed alarm a few times, the past few weeks. I thought it was maybe the wind or too sensitive motion detector or something and blew it off. Then one day it would not start AND jumping would not start it either. By not starting I am saying it would not CRANK at all. Full juice (12 volts) at the battery. Mystery. Since it was Friday I left the car at work and came back the next day to work on it. BMW alarm have a feature that cuts the ignition if it detects is being stolen. I figured my car forgot who its owner is (lol). So, I set out to disarm the disarming of my ignition (ie, deactivate the alarm). I went to the fuse panel located in the trunk and pulled the alarm fuses. No joy. My plan failed. While I was backed there I tested all my other fuses and checked the SERVOTRONIC fuse (fuse number 55). I noticed that when I put the fuse back in the alarm chirped! Hmmm. That is not an alarm fuse, the servotronic is apparently some brain that works with sensors, power steering, power windows and the alarm. It is a good fuse. Since that fuse just activated my alarm I figure I could deactivate the alarm and deactivate the ignition cutoff by temporarily removing the servotronic fuse. BINGO car starts like a champ.
Weird: Servotronic fuse OUT, car starts.
Servotronic fuse IN, car won't crank
So, I got my car started but it is not fun driving without power steering, power windows, and I am sure a couple other power things. Plus I can not lock the car without that fuse in! Weird. There is something wrong with some sensor that is telling the servotronic the car is being stolen and it is cutting off the ignition. I will be doing more troubleshooting this weekend.
Anybody else have clues armed with this new info?
Dutch girl, how do you finally get your car started? Try my trick. That will confirm that this is NOT a starter problem, but a theft immobilization problem instead. Anyone know of a master reset procedure for the alarm?
PS. Good news is that my biceps are growing MASSIVE without that power steering working. hahaha.