Hello,

The car is a 1991 420sel and when opening the driver door the dome light or exit lamp on the door does not function. The driver's power seat does not function when the door is open as well unless you turn the ignition on. The front door on the passenger side turns on the dome light and exit lamps when it is opened.

I checked the switch on the door pillar and it works. There isn't any power going to it though. When the door on the passenger side is opened, I can hear the click of the relay in the fuse box. I don't hear anything when I open the driver door. Are there separate relays for the driver and passenger doors? I checked all the fuses, they are all good. Any help would be appreciated...

Thanks

Nolan

p\seat,dome light
 

Check your fuse box there is a Power seat Diode replace the diode (color gray like a plug),dome light will be the warning module relay locate under driver side lower panel,right next the cruise control unit.(004 545 07 32) hope this help.

Thanks for the tips. Are there separate relays in the warning module for the driver and passenger side door or is it just one relay for both doors?

Nolan

91 420sel dome lamp inop from driver door
 

The fault is in the warning module. It also has the headlight on buzzer citcuit in it. It gets damaged when the left frt puddle lamp falls out and the door closes on it. the module fries itself to protect the fuse!
It lives under the dash, left sie, black box, 1.5x1.5 inches
Sometimes repariable with a good solder hand...

Thanks for the info. I was planning to check out the warning module sometime soon. Hopefully I can repair it.

Nolan

The warning module/seat belt reminder was the problem. I opened up the old one and saw too many diodes that I didn't have time to mess with. I ended up buying a new one with a 1 year warranty from MB. Now the power seats, courtesy lights, seat belt reminder, and buzzer all work when the driver door is opened. Thanks again for everybody's input.

Nolan

My car is suffering from no dome light when the driver's door opens also, (1989 560SEL). I just dug around under the dash, and found the part number referenced above, (004 545 07 32), by MB Stars. Is it just the little guy that unplugs? About 1" x 1 1/4" x 3/4" deep, six contacts in it? Or is it the whole box behind it? I pulled mine out, opened it up, and it just appears to be 4 resistors on a small board.

Thanks for the info!
John

The warning module/seatbelt reminder has 8 pins. I don't know if the '89 model w126 has a different part #. It's right beside the cruise control module which is a much bigger box. I found that it's the easiest to pop the old module/relay out of it's "box" or housing instead of trying to remove the screw on it's bracket. Then you can just pop in the new module in the old housing. It's saves you the grief of removing the cruise control module and bracket. It's a real pain to put it back up there. Good Luck.

Nolan

Finally got to my dome light problem. Here are my results:
I attempted to pull the module from it's housing, as suggested, but was unable to figure this out as it sat under the dash. After I removed it from the car, I saw the small tabs which retain it in the housing. This is what I would do next time, as Deezelguy suggests.
I ended up removing the 10mm nut from the bracket holding both the cruise control relay and the warning module relay, unplugging the wires and then taking the warning relay apart on the bench. More on this nut later.
Upon inspection of the warning relay, I found some reddish brown crud on the PC board itelf. I wiped it off with a clean rag, and then check the continuity from pin to pin, where it should be according to the schematic diagram on the CD Rom. I found one place where I had no continuity. The problem was one of the solder tracks, (not proper term, I am sure), on the PC board was missing a 1/16 inch. This was from where the pin connects to the board and the first diode.
I had not purchased a new relay, so I soldered a small, (1/4 inch long), jumper on the board. Tough job, but it worked. I would not attempt to solder the board itself, unless you are an expert at this. Too easy to mess the whole board up.
Installing the relay into the case, left me with only mounting the relays back into the dash. I found that what I thought was a stud threaded into the casting around the master cylinder rod. Actually, it is a bolt, captured in the casting. I discovered this when the bolt pushed through, fell into the casting as I attempted to mount the bracket.
My solution to this was to stuff a rag in the casting, around the master cylinder rod and boot, stopping the bolt from pushing through the casting. MBenz engineering provided a hex shaped hole to trap the bolt from turning in the casting, (dunke shein!). So this was sufficient to do the job. Mounted the bracket, connected the wiring harness and now I have light!
Not too bad, but it is one of those jobs where you wish you had really tiny strong fingers, and no shoulders to allow you to crawl around under the dash.
Any questions, shoot me an e mail.

John,

I need to replace my warning module. do you remember the tabs that need to be adjusted to take it out of its housing?

My dome light is not working when my left door is open.. but does with right door. No "key left in car" buzzer nor "lights left on" buzzer either.

Funny thing is that the seatbelt buzzer IS working. Are they all controlled from the same module?

Willy

I documented the procedure here. If the link doesn't work, copy and paste it.

http://diesel.web1000.com/5/