Questions and Answers

BMW 733i Electrical Power Loss Q. 1984 BMW 733i, I am having problems since replacing the battery. the speedometer and computer are not working right. The speedometer is jumpy and the on board computer is not working at all. Any idea as what to look for?? I have checked the fuses they are all good but not getting power to all of them. Is there anything else I should look at?? Thank you, Rob

A. It sounds like you are not getting power to the Main Power Distribution box under the hood. This feeds power to the Secondary Power Distribution box which feeds power to the fuses.

I would suggest checking any fusible links at the battery and work back from there. There is a large red wire going into the under hood box (I assume you checked all these fuses as well) so make sure you have power there at the box. Then there is a green wire that goes from the box to the ignition switch, make sure you have power at this wire out of the box and into the ignition switch. I think you'll have found the problem before you get to the ignition switch.