E28 electrical problems

[Eric K]

Here is the deal. The gauges (tack, fuel, engine temp...) usually don’t work on my 1987 535is. I say usually because when I go over some bumps they all turn on. What is causing this? I checked the ground, it was tight so I cleaned it and retightened it, any other ideas?

Also when the car is running the battery is putting out 14v but when turned of it is only making 10v. Is this a bad battery or could there be another problem?

Let me know what you guys think, thanks

Eric

[healtoeit]

Sounds like a bad connection, the bump could reconnect then disconnect the wires

[genphreak]

Here is the deal. The gauges (tack, fuel, engine temp...) usually don’t work on my 1987 535is. I say usually because when I go over some bumps they all turn on. What is causing this? I checked the ground, it was tight so I cleaned it and retightened it, any other ideas?

Also when the car is running the battery is putting out 14v but when turned of it is only making 10v. Is this a bad battery or could there be another problem?

Let me know what you guys think, thanks

Eric

A good battery gives 12.5V connected to the car (nothing running). 10V indicates a lot of drain or a bad battery. Giver it a good slow charge, check the electrolyte levels and then the specific gravity once it is well charged. Check the Main relay, power protection relay and your fusible link- that is the most common cause of general weirdness, even if it looks okay it can still be bad from age and corrosion.