Hi, I have a 318i, the earlier M43 engine. When the ignition is switched on, the oil pressure light and usual warning lights come on, but not the main ignition/battery warning light. Always been like this in my ownership, I assumed a bulb gone and ignored it. The car is definitely charging and everything works Ok with no other electrical problems that I know of.
Until I switch the rear screen demister on, then the main battery warning light comes on. Two part question really - what is the source for the battery light when the ignition is switched on, any clues on fixing this? Second - any ideas why the light comes on with the demister?
I believe that the car is still charging with the demister on, but never tried leaving it switched on just in case. Thanks for any ideas or links to a wiring diagram.