w126 Looking for relay information - PeachParts Mercedes-Benz Forum

phlfly · #1 12-10-2017, 06:35 PM

So my story is when I opened a driver door overhead light and door step light will not come on. So today I took my volt/ohm reader and jump into. Passenger door is working properly. So I don't getting 12 V at switch in the door. I swapped switches and same thing. I have good ground from switch ground wire to car ground (use metal part of the engine start switch).
Than when i was reinstalling everything back, I noticed passenger switch will activate some relay. I was just playing with it, I heard clicking sound under the hood. Looking at attached diagram below M to K6 pin 6 is relay called Power seat window. I removed it, check , it looked fine no visual burning marks, just very old as see. Than re-installed and none reading or overhead light were working, emergency light didn't work too, radio/cd player stopped working, sun visor lights didn't work too. I drove as is few miles and suddenly radio came back and else too. Very strange. It's like something didn't energized for some reason.
I would not touch this relay anymore, it really should not effect door light anyway, left door will not active this relay, no clicking sound on this relay.
So looking at schematic, N2/4 is faulty, may be diode? Is anyone experience with this before ?

Thanks

Diseasel300 · #2 12-10-2017, 07:39 PM

The dome/courtesy lights are activated through the seatbelt warning module up under the dash. It's an extremely common failure item. You can replace the warning module, or you can do some hack wiring to tie the passenger side and driver's side switches together. What usually kills the warning module is the courtesy lights in the doors falling out and getting slammed in the door.

phlfly · #3 12-10-2017, 08:50 PM

Quote:

Originally Posted by Diseasel300

The dome/courtesy lights are activated through the seatbelt warning module up under the dash. It's an extremely common failure item. You can replace the warning module, or you can do some hack wiring to tie the passenger side and driver's side switches together. What usually kills the warning module is the courtesy lights in the doors falling out and getting slammed in the door.

How did you run wire from passenger side, any advice ? thanks
I read already it's like b... and expensive to replace this relay.

Diseasel300 · #4 12-10-2017, 08:55 PM

The seatbelt warning module isn't expensive and isn't a huge deal to replace. Forget removing the entire body, just release the guts and replace it. Takes less than 5 minutes. I didn't do the hack wiring job on mine, I replaced the module. Searching this forum should turn up the hack wiring instructions if that's the route you wish to go.

phlfly · #5 12-10-2017, 09:57 PM

Quote:

Originally Posted by Diseasel300

The seatbelt warning module isn't expensive and isn't a huge deal to replace. Forget removing the entire body, just release the guts and replace it. Takes less than 5 minutes. I didn't do the hack wiring job on mine, I replaced the module. Searching this forum should turn up the hack wiring instructions if that's the route you wish to go.

Where did you buy it this module ?
I think it's located underneath steering column ?

Diseasel300 · #6 12-10-2017, 11:28 PM

Ebay. 1986-mid 90s all have the same module. It's fastened to the steering column above the driver's footwell. It's on the same mounting point as the cruise control amplifier. A SERIOUS pain if you want to remove the entire module (hence the suggestion to replace the guts and leave the case in place)

phlfly · #7 12-11-2017, 09:25 PM

p/n - 012 545 68 32?