SL/R129: SL500 interior light & power seat problem
Thread Starter
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Joined: Sep 2004
Posts: 19
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SL500 interior light & power seat problem
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!
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!
Last edited by rkubara; Sep 8, 2004 at 02:09 AM.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
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
- FD
Thread Starter
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Joined: Sep 2004
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Originally Posted by 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
- FD
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.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
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
-FD
Member
Joined: Aug 2009
Posts: 154
Likes: 0
From: South Florida
2005 S 500
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!
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!
If So What Was Wrong ??
Thanks
Harley03joe
Newbie
Joined: May 2014
Posts: 2
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R129.066 1990
The same light problem
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...?
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Member
Joined: Aug 2009
Posts: 154
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From: South Florida
2005 S 500
Your Int Light Probles Is
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!
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!
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Newbie
Joined: Apr 2016
Posts: 1
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Mercedes SL 500; 1999
Follow up, did recommended relay part # 012 545 68 32 fix dome light problem ?
Thanks,
Dustin
Newbie
Joined: Jul 2023
Posts: 1
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1992 SL 500
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.
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.
