I have been slowing piecing back together a 87 300D and just when things are coming together something strange happens. All the lights work on the exterior of the car, but the light out indicator on the instrument cluster comes on if I turn on the fog lights or the headlights. Here's the strange part, if I have the headlights on and pull out on the switch to turn on the fog lights the wipers start and run through a cycle like the washer has been pushed. Same thing happens when switching from low beams to high beams and even did it one time when turning a turn signal on.

Should I be suspecting the combination switch on the column or is there some other gremlin hiding under the dash that could cause that. A little background, this car has been sitting for over 4 years now, it was hit left left front but all the wiring has been repaired for some time now. This just started.

Any thoughts? I would really hate to just guess it is the combo switch but that seems to be the only thing in common with the things that are happening.

Sounds like a ground issue to me.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

Very well may be, I am still looking but I will check for a loose ground. The only things that have been messed with were up front on the left side so I will hit that area.

Thanks for the input!

I would check the ground behind the left headlight then ... could have to do with the headlamp wiper motor which is ground there along with the lights.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

That could be my problem then, the headlight wipers were not working and I decided to remove them and installed the blanking plates you can get here on pelican parts. If that motor is a ground do I need to ground one of the terminals from the wiper motors on the harness? I just did this a short while ago so it coincides with my problem.

Non working headlight wipers!? I have a cure for that...
Parting out $10 each.

Mind you I've adjusted the cams in each so the resting position is in the vertical position, done for three reasons: blocks less useful light coming out of the headlights at night, more aerodynamic, looks different and says with a louder voice "hey, there's fricken wipers on these headlights how cool is that?! And I guess it's more of a visual match with the diplomatic flags mounted on front bumper corners. You gotta get a set of these flags, you can park anywhere with 'em.

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Cheers!
Scott McPhee

1987 300D

The headlight wipers themselves aren't the ground. But there is a major grounding point behind the left headlight for the lights and wipers. Take out the HL and look for a bunch of brown wires tied to the inner fender.

Yeah, I would check this bundle as maybe it either got disturbed by the collision damage or when you went to disconnect the wipers. Or could be some damaged wiring that's shorting. I would think (and someone can correct me if wrong) that just leaving the wipers unplugged would be fine, the circuit would just be open.
The bundle is right behind the wiper motor, so you could have jostled it while removing the motors.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

I got to check the ground point behind the headlight this evening. From the wiring diagrams there should have been two ground wires at that location. There was only one, after a little looking around I found the culprit. There was a wire that had been repaired after the accident (with a fork terminal) that had been pulled off. I replaced the fork terminal with a ring terminal and replaced the wire. Started the car and checked it out, all the problems were gone.

Thanks everyone for the great advice!

Great!

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http://i284.photobucket.com/albums/l...aman/Fleet.jpg

Peach Parts W124.128 User Group.

80 280SL
85 300SD
87 300TD
92 300D 2.5 Turbo
92 300TE 4Matic

I had been following this thread and I had gotten to the point of pulling out my 124 wiring diagram and studying it. I too suspected a missing ground and started a reply but got called away and never finished it.

According to the diagram, the wiper motor grounds are independent of the headlight grounds.

In my control system work, whenever I get a weird problem the neutral/negative side of the circuit is the first thing I check. 99% of the time that is where the problem is found.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

with apologies to Beyonce

*put a ring on it, ya got to put a ring on it*

Seriously use a ring terminal for your repair, or it will fail again shortly.

I would use an uninsulated terminal, crimp it with a quality crimping tool, then solder it for good measure.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech