I know that sometimes the contacts on your starter solenoid get worn or 'burnt' and the solenoid magnet pulls the contacts togethor but sometimes it just doesn't make contact. You still have power to all your normal start circuits (fuel pump etc.) because of this. I know on Toyotas (nippon-denso) you can replace just the contacts, but I don't know if you can do this to a Bosch starter. Jake, Tucson AZ 89 M3