rkubara

My 4 interior lights come on when the passenger door is opened, but do not when the driver door opens & it is not the door switch. I was working on the drivers door and shorted the door lamp when inserting it. No blown fuses under the hood or in trunk. Also, the mirror/dome light does not come on with either door when the switch is in the correct position & the overhead switch has been replaced. This is an old problem.

Furthermore, the power seats no longer work when the drivers door is open, only when the key is ion place or when the passenger door is open. The problems are related.

Must be a damaged PCB or relay but 4 local Mercedes dealers will not tell me what part is damaged, they tell me to bring the car in. It was suggested to me that the main light relay box in the fuse box is the problem, it was replaced and did not make a difference. If I can get the elctrical diagrams I could find the PC or replay that is at fault!
Can anyone tell me what component is damaged and where it is?
Wife is annoyed and wants the interior lights and power seat working again!

Floobydust

Have you checked the door switch? It is located on the A pillar just below the top door hinge. The switch is activated when the door is not pressing on it when open. If it has become dirty or jammed it cannot fully extend to make contact. This would be consistent with what you describe.

- FD

rkubara

I have checked the door switch. I used a meter, swapped it with the passenger one, connected the two wires without the switch and even supplied a ground to the wires just in case. It is not the switch.

It must be a relay that the door switch provides power to. If someone has electical diagrams and can tell me were the wire from the door switch goes, brown with a grey stripe and red bands.

I now realize my seat belt buzzer & light does not activate when I take it off while driving. Not sure if this is related.

Floobydust

I have schematics for the R129 series on DVD ROM. I'll see if I can look it up this weekend (the search engine for the DVD ROM is terrible and the details for all years are not always there). I'll post what I find.

-FD

Harley03joe

I Know This Is Very Old Post But Did You Get Your INT Lights Working ?
If So What Was Wrong ??
Thanks
Harley03joe

perverso968

i read forum post but not have a valid answer because have the same problem with interior light when open passeger door its come on but when open driver door nothing do..? i check the door suitch and same ok. it no have corrent in any wire, all occours after lamp change on pedal and it make a short circuit in the socket because it is broken, after leave an replace the broken lamp socket it not come on never but at passager door open it come on and all other lights to. i check all fuse on fuse box on motor side and trunck side but all its ok. when i active the passager door suitch i ear a tick of a relay and can't locate it...? maybe is a fault relay or another fuse missed in some hide side...? please can help me to locate fault...?

perverso968

sorry i have a 1990 SL500 R129 California

Harley03joe

Your Problem Is The Relay Behind The Pass Side Air Bag, Its On The Plemem Plastic Case In A Clip I Beleave Its Part # 012 545 68 32
Here Are A Few Pictures
Harley03joe

Dustin Bly

Please advise if part number reference above solved the problem of dome light not working when one or both doors are opened. Also, the floor lights and door lights do work with one or both doors opened. The reading domes lights do work in all positions.

Thanks,

Dustin

KTD_SL500

Has anyone solved this issue? I have exactly the same symptoms.

BUT there is no N2/4 Relay behind my passenger airbag. (1992 - 500SL)

I believe I hear a relay under the drivers seat that switches on/off when closing the passenger door.