I am have trouble with the dome light in my 1987 420SEL. The back light works when the back doors open. The front map light and dome light both work when selected by the switch. When the switch is set for the dome light to come on when the doors open nothing happens. It dose not matter if the drivers door or the passanger's door is opened. Both switches check ok but there is no voltage at the switch.

thanks

...no voltage at the switch...

The bulbs in the dome lights are constantly powered and switching on/off is controlled by grounding the bulb...

I presume that the W126 S class dome light is similar to the W124 and later W201 dome lights...and these are known for their malfunctioning switches after several years of service.

You can get out the dome lights, dismantle the unit and clean the switch. If you are lucky it will bring you the requested light in the dark, if not...you might have to get a new dome light...

greetingz,

MBenz,
How can I get the domelight out?
Thanks,Clauser1

on the W126 push it to the right (as you sit in the car) until the driver's side pulls down then the whole thing will come out.

Thanx DJ,

Appreciate it.

Clauser1