Interior lights problems 1992 SL500

[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.

Also, the mirror/dome light does not come on with either door when the switch is in the correct position. Switch has been replaced.

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. :x
It was suggests the main light relay box in the fuse box is the probelm, it was repalced 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 part is damaged and where it is.

 

[webby]

Hi Ron,

Strange One!

Just a stupid question, have you checked the fuses in the trunk?
They are behind a little black cover on the R/H side.

Other than that it sounds like a connection somewhere between the door switch and the relay.

Webby

 

[rkubara]

fuses in trunk

Yes I have checked the trunk fuses. Please keep in mind the lights work with the passenger door, but not the drivers. Thanks for the suggestion.

 

[Spike]

Are you sure its not the cables leading into the door?

Often the cables get damaged in the door hinge area due to repeated movement of the door opening and closing. . Might be worth temporarily testing the circuit using some new cable or at the very least, checking the resistances whilst wiggling the wires.

HTH

 

[guydewdney]

ok - this is a 500 E, but its probably very similar

http://www.autolib.diakom.ru:8001/CAR/Mercedes-Benz/1992/500E/SYSTEM WIRING DIAGRAMS/4346.pdf


http://www.autolib.diakom.ru:8001/CAR/Mercedes-Benz/1992/500E/SYSTEM WIRING DIAGRAMS/4347.pdf

 

[rkubara]

wires and wiring diagram for 500E

Spike, thanks for the suggestion. I had checked the ground wire and it is grounded. I cannot check the other wire as I do did not now where it goes. I have recently learned that both door switches and the seat belt switches go to the seat belt warning relay and to another relay under the hood, which then powers the interior lights etc. I now suspect my seat belt warning relay may be toast and will replace it. It is in the passenger foot well up behind the airbag, not too bad to get at.

This drivers door wire goes to the seat belt warnig relay and I get a reading at the connector from the switch to the relay, so it is not the wire.

Guydewdney, thanks for 500E wiring diagrams, but unfortunately they are completely different to the 500SL. It was worth a try!

 

[teky]

well done rkubara im impressed :idea:

 

[rkubara]

tecky, thanks for the kind words, but it is not resolved. I have found that both door switches go to the seat belt warning relay and also to the left and right backrest lock safety package relays. The passenger lights still go on and off with the passenger door even with the seat belt warning relay removed.

This now leaves the backrest lock safety package relays in questions. There are two, one for each door. They are called N32/7 & N32/8. I suspect these relays let the power seats move when the doors are open and no key. The 3 programs will work because of these relays. Furthermore, as well as my lights not going on the drivers side, the drivers seat won't move without the key. But will if the passenger door is opened.

I now suspect that the N32/7 relay is toast and N32/8 does work, this would be why my passenger door trigger the lights and lets the seats work. I would like to switch the relays, but do not know where they are.

I do know the coordinates 12L & 13L. Can anyone tell me where these coordinates are?[/url]