1988 Mercedes 300ce No voltage to drivers side fog lamp

Tiny
MACK1604
  • 1988 MERCEDES BENZ 300CE

Electrical problem
1988 Mercedes Benz 300ce 6 cyl Two Wheel Drive Automatic 178000 miles

I have no voltage to the drivers side fog lamp and the bulb is good. Passenger side works fine. They are turned on the pulling out the headlight switch. One fuse handles both and it's good.

Do these lights wire directly to the headlight switch or is there a terminal somewhere between the switch and the lights?

Even though I can get both fog lights working by tapping into the passenger side, it doesn't solve the problem of the outside bulb warning light being on in my dashboard.

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Saturday, August 8th, 2009 AT 12:53 AM

9 Replies

Tiny
JACK42
  • MEMBER

I have forwarded your question to our M/B tech. He will be with you shortly, thank you for your patience

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Saturday, August 8th, 2009 AT 8:59 AM
Tiny
MACK1604
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Are your Mercedes guys on vacation. I have not recieved any response to my question.

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Wednesday, August 12th, 2009 AT 10:32 PM
Tiny
JACK42
  • MEMBER

I apologize for the delay. My software doesnt show anything for external lighting on that vehicle. If you can tap it and it works, there is a bad connection in the light itself. It may have a bad ground or an overheated/poor connection at the bulb.I have even seen the bulbs themselves do what you describe. This would change the resistance causing the bulb warning to illuminate.

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Thursday, August 13th, 2009 AT 7:24 AM
Tiny
MACK1604
  • MEMBER

Where does the wiring for the drivers side fog lamp teminate? Is there a juction or does it run straight to the headlight switch? And once again, it's not a bulb problem. There is no voltage in the positive wire that goes to the lamp. Thanks.

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Thursday, August 13th, 2009 AT 11:23 AM
Tiny
GFIMOTORCARS
  • EXPERT
  • 681 POSTS

Do you have power at the fuse for the fog lamps?

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Friday, August 14th, 2009 AT 2:23 PM
Tiny
MACK1604
  • MEMBER

Yes I have power at the fuse for the fog lamps.

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Friday, August 14th, 2009 AT 3:29 PM
Tiny
GFIMOTORCARS
  • EXPERT
  • 681 POSTS

If you have power at the fuse and it is not making it to the fog lamps then you have either a cut or grounded out wire. Using your multi meter check for continuity between the positive terminal on the lamp connector and the fuse. If you have no continuity then you are going to have to manually trace the wire from the light back and find the split or an area where it is grounding out. You may have to open up portions of the harness to complete this inspection. Also when the lights are on try shaking the harness. If the lamp flickers on and off the you have a short to ground somewhere between the fuse and lamp, if not you more than likely have a cut wire between these two points.

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Friday, August 14th, 2009 AT 3:59 PM
Tiny
INDYZ12
  • MEMBER

Hi.
I know this is a late reply, but the answer to your problems is listed below!
First, I suspect you have diagnosed there is no voltage to the foglight pin in your headlight loom.
What you want to do is remove the fusebox lid, and you will find 2 screws underneath.
Remove these. Now remove the 2 screws on the relay box cover (Behind the fusebox)
Once you have done this, you will see your headlight contol relay. This is the longest and biggest relay of them all.
Remove it carefully and clean the contacts.
Whe you replace it, make sure it is secured to all 3 coonectors, esspecially the centre one as this is what controls the fogs.
I had the same problem. Let me know if this fixes your issue.

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Thursday, March 25th, 2010 AT 6:08 AM
Tiny
KARAM123
  • MEMBER

It may be dirt around it or bad connection

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Tuesday, July 6th, 2010 AT 6:26 AM

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