1991 300D 2.5 w124. I've never payed much attention to this until recently. Is the rear dome light suppose to come on whenever any door is opened? Presently it only comes on when I open the rear(driver side) door. Another question. What is the true function of the light switch on the panel? When I push it in the only light that comes on is the light on the floor(passenger side). I read a few posts about the lights switches in the doors, do they need to be cleaned? Where are they?

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1995 E420 152k
1991 300D 2.5 348116 daily driver
1992 300E 2.6 196k-work in progress(head gasket)
2002 BMW 745Li 93k

When a front door is opened the front entry lamps and front dome lamp should come on. When a rear door is opened the rear entry lamps and rear dome lamp should come on. When the dashboard rear dome lamp switch is turned on only the rear dome lamps should come on.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

There's definitely a problem somewhere. Where should I look first?

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1995 E420 152k
1991 300D 2.5 348116 daily driver
1992 300E 2.6 196k-work in progress(head gasket)
2002 BMW 745Li 93k

The rear dome light is hot all the time, the ground is switched, perhaps this will help your search.

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Gone to the dark side

- Jeff

Check the wiring in the rubber boots between the B-pillar and the rear doors. The rear door switch wires run through those boots and can break from many years of bending. You have to remove the B-pillar covers (where the front seat belts have their retractors) to get at the wiring. The switches themselves can be removed and checked for continuity. You already know that two of the bulbs and their wiring are good. Opening either rear door or pushing the dash switch should turn on both puddle lamps and the rear dome lamp. Make sure the other puddle lamp is OK.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

How do I remove the pillar covers?

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1995 E420 152k
1991 300D 2.5 348116 daily driver
1992 300E 2.6 196k-work in progress(head gasket)
2002 BMW 745Li 93k