Thanks for the reply. Yes the OBC works fine. No the trip doesn't reset. The only other thing is, I think it's the bulbs, the trip and odometer reading are very faint to read. Not sure what the stomp test is? Thanks.
Quote Originally Posted by Warren N.CA
Seriously, you should check to see if your OBC is calculating and displaying mpg data. If not, the problem should be corrected there, possibly by replacing the OBC with a unit from salvage.

Also, this problem may be caused by bad capacitors inside the cluster. Do you have any other issues with the cluster? Does the trip odometer reset with each engine start? Does the stomp test work? I would think virtually every '89 535i would have some bad capacitors in the cluster. Changing them is not difficult for someone with electronics skills.