I am so confused...
I was testing a light (one of the ones used for the glove box, and under the doors in a 126) earlier today. I removed the driver's side courtesy light (under the door) and used the leads to test another similar light. I plugged it in and got light. I then pressed the button that is pressed when the door closes and the light went out. Good. When I released the button the light went on. Good. So, I removed the light and replaced the one that belongs there...but no light. I checked the bulb and it is okay, next I checked the fuse...also okay. I then noticed that the overhead light (above the rear view mirror was not on either. So...when opening the driver's door there are no lights, however when I open the passenger door all three (overhead and both doors) light up. The only logical problem is the switch, although I don't see how. I will switch out the switch with the passenger side later, any ideas as to what happened??

I would imagine that when you manually moved the switch, you pushed it past where it normally goes to. For whatever reason, this was enough to break it.

Well, I just switched the button with the passenger side and nothing has changed. Any ideas??

Look at a wiring diagram you will find that the drivers door switch doesn't go straight to the lights as the passenger side does.

It passes through the seat belt warning device or alarm or some controller. Its in the drawing. There is a diode or something that burns out in the controller. We have fixed a number of those controllers and bypassed others.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

A diode? Why can't this be simple...
You wouldn't happen to know the location of the evil diode, would you?

I have found the location of the controller (at least in a diagram). It looks like it's under the steering wheel (belt warning module N2/4). Do I have to replace the whole module, or is there something internal that can be replaced? I'll get in there later today hopefully.

We have fixed everyone that anyone wanted fixed, by opening the box and following the circuit and repairing what is open. I can't remeber as I don'r do it. We have an electronic lab that does all the internal work in house. I think its a diode but it might just be solder contacts.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Looks like I wont be getting to it tonight...I'll check it out tomorrow. Thanks for the advice

Okay...here's what happened.
I found the piece in question, under the steering wheel, near the parking brake. It is attached to a plate which also holds a box with a VDO logo on it (didn't bother to check what that thing was.) The plate is held in place by a single nut (circled in blue.) Once removed there is a clip that holds the main plate to the belt warning module. After getting the module free I pulled out its guts and tried to find the problem, but everything looked good. I checked the price of the module and it costs just over $70. I wasn't really looking to spend $70 to have a light turn on when I open my door so I looked for other solutions. I examined the wiring diagram and found that if you short pins 5 and 7 on the wiring harness the lights will work as they should, but no warning buzzer (it is part off the module in question.) As I was examining the module looking for a way to get the buzzer wired in I found the problem, one of the circuit traces on the circuit board was toasted. Long story short, 10 minutes and some bad soldering later everything works as it should. The hardest part was getting the VDO/module/plate back on that nut/bolt. Next time I'll leave the whole thing in place and just pull the module guts out. Anyway, now I'm wondering what to spend my $70 on...

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the problem...

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fixed

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