One more question ...

On my 95 e320, The rear dome light has stopped coming on when turned on by the dash switch or either rear door opening. I already tried the bulb. Is it common for there to be wiring problems to the bulb -- this doesn't seem like a place that would be subject to a lot of corrosion or mechanical stress.

The problem was intermittent at first, but now I can't get the light on at all.

Could this be related to problems with lights on my pushbutton unit and the light behind the shifter display?

Thank you very much.

All advice appreciated.