Hi, actually i am an e30 noob too. but i have been a mercedes and BMW mechanic (newer models) in the past. From what you say the problem is clearly common to those items you mention. I'd start with posting the issue in the electronics forum, to see if anyone else has had this issue before. My knee-jerk reaction is there might be a system relay that is faulty, but that is a guess. Good luck with it. ;)
