I have a 97 528i. The starter is new and I have replaced the ignition switch.
The problem is that the starter will not engage. It doesn't do it all the time and sometimes after coming back to it 5 minutes later it will start. I have check the fuses and my mechanic said it was something to do with the security system. I try unlocking doors/locking doors and nothing will work until the car wants to engage. Any ideas???
when you say it doesn't start, do the dash lights/symbols show up, or is the dash blank?
Have you tried moving the gearshift to neutral and trying to start?
Not sure why you mechanic "thinks" it's the security system? Has he not scanned the car for trouble codes yet?
Does you dash show a security light?
It's the little spad fitting on the bottom left of the photo (not the drawing).
As you, or someone, turns the key, the test light should go on--that actives the starter solenoid.
So if the test light goes on when the key is turned to the "crank" position, then the trouble should be in the solenoid or starter motor. As far as I know, the only thing that interrupts this circuit would be the immobilizer or the neutral safety switch---but I don't have the wiring diagram for the whole car so there might be some other little devil in there.
If the light only goes on now and then when you turn the key to crank (intermittent) then we'd suspect the ignition switch or some glitch in the wiring between the switch and the solenoid.