1987 Mercedes Benz 420sel

MWHIT1230

MEMBER
1987 ALL OTHER MAKES ALL OTHER MODELS

Passenger side headlight goes blank when on dim. New bulbs do not help. Fuses have been checked. What could be the cause?

Wednesday, January 17th, 2007 AT 8:47 PM

3 Replies

MATHIASO

MECHANIC
1,209 POSTS

Formerly one of the most basic circuits in the vehicle, the headlights have automatic dimming light-sensing switch to automatically turn them on, and auxiliary driving lights integrated into them. Keep in mind that these items have their own controllers and relays that operate them. Always turn to your DMM and wiring diagrams to isolate problems.
The dimmer switch in older application is connected in series between the switch and the headlamps. When curent is turned on the dimmer switch directs the curent to the selected bulb.
Checking that dimmer swicth may help you find the answer of your question.

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Wednesday, January 17th, 2007 AT 11:08 PM

MWHIT1230

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4 POSTS

I would believe that could work, but this vehicle has no automatic headlight dimmer. It's done with the signal lever. It must be something else. What's unusual is that it's only the passenger side that goes out.

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Thursday, January 18th, 2007 AT 11:49 AM

MATHIASO

MECHANIC
1,209 POSTS

The dimmer switch in older application is connected in series between the switch
(the signal lever ) and the headlamps. When curent is turned on the dimmer switch directs the curent to the selected bulb.
Checking that dimmer swicth may help you find the answer of your question.
You need a wiring diagram and a DMM.

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Thursday, January 18th, 2007 AT 10:57 PM