Hi all,

I'm new here. Just bought an '85 300TD wagon and really loving it. Plenty to tinker with. But one thing is bugging the hell out of me and I have to get this thing inspected this week:

RIGHT FRONT blinker is not working.

*fuse is okay
*bulb is okay
*flasher unit under center console seems to be functioning fine
*hazard switch seems to be working fine, as the hazards do work.
*ground seems to be fine but it is kinda rusty and I don't have another tiny wrench to get on it to really check it out.
*wiring harness seems fine. Had cobwebs in it but I cleaned it all out.

The weird thing is that the flashers were working on all four corners when I started messing with things, now they right front (the problem child) isn't working.

There's some other weirdness when using the parking and standing lights but nothing too bothersome. ANY HELP with this signal/flasher issue would be much appreciated. I've read all the other threads I can find and nothing is making sense.

Thanks!

Welcome to the forum!
the Diesel forum is good for this problem, I'm sure we'll find the issue and get it sorted with you.

problematic blinkers are a PAIN to sort. often it's a problem with the emergency flasher, but your issue sounds like a flasher, or fuse to me.
open the fusebox cover, (hold on to the bolts that lock it down, as they fall out.)
then at a minimum, rotate all the fuses. I would recommend pulling them all, and cleaning with a soft cloth and a metal polish or de oxidizing chemical then replace with new copper fuses...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

As was said pull and replace all your fuses with copper or brass ceramic fuses....cheap on eBay see a nice package for 10$....also the dirty rusty ground is probably causing the issues....should be an 8mm bolt, remove it and use sand paper to clean the contact area on the inner fender and the o ring....until you have a nice shiny area....bolt it back on and cover with grease to prevent further rust...

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Most electrical gremlins on these cars can be cured by cleaning harness plug contacts and ensuring all the ground wires you can find have good and clean contact.

Phil Forrest

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1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

What is the advantage in swapping out the fuses? Corrosion resistance? Better conductivity?

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

on my 240D, the right front and right rear blinker are wired together. if your right rear IS going on, then you have a faulty connection before the last light, probably in the chassis ground. if your rear right is not going on after all, then i think it's likely that the plug at the turn signal switch or the hazard switch has come loose.

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'77 240D, 504H, OM617.952, etc.

Both.....aluminum and copper have never gotten along well.....the fuses are aluminum and the contacts are copper.....add in moisture and 20+ years......they all just don't live happly together....

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Thanks everyone. I've already got some replacement fuses on order, and I'll take a deeper look at the ground today...

Turned out to be a break in the right front blinker harness wiring (ground wire) in addition to a bad socket. I grabbed a used one on ebay, spliced it in and havent had a problem since.
Good luck and welcome!

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1985 300D 172,110mi and goin' strong

Just saw this thread.

When you said "problem with both the marker light and the blinker, only in one corner" that screams grounding issue to me.

Any time you have weird issues on the exterior lights, and you know for a fact the bulb is good, the next place to look for is the grounding of that socket.

Especially when the ground point is shared with other things, where the bulb can find ground via some other load that is still touching the socket grounding wire, but the wire is not touching the car body.

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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

Jooseppi ... aluminum elements not only blow, they melt. Copper or brass one wont melt under normal conditions, they just blow.

Changing all your fuses and cleaning the fuse terminals is a great way of avoiding potential issues with your electrics.

It doesnt hurt to check the proper fuse rating shown on the inside of the fuse box cover too !

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

UPDATE: it was the ground. Got it all cleaned up and working much better now. Put some dielectric grease on it too which I think helps.

Thanks,