Was driving my 85 300D. All of a sudden no turn signals. Other lights work.

I test the 4way flashers and they work. After cycling the 4-ways every thing is back to normal. Apparently had dirt or corrosion in the contacts of the switch. I looked up the schematic and noticed that the power goes through one set of contacts in the 4-way switch before it goes to the blinkers.

Might be something to think about if your turn signals quit working.

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

My turn signals buzz but don't blink. Same for hazards. I'm wondering if I have a bad signal unit and/or hazard switch. 84 300 TD.

I have to manually simulate signaling by moving the lever.

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

Do all the bulbs light up?

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

Sounds like the relay is bad. It's under the console around the gear selector.

All the 123's and a lot of the other models use the same relay for the hazards and the turn signals. The early ones the hazard switch is also the relay for the hazards and the turn signals. The later models the hazard switch is separate from the relay but they both still use the same relay which is under the gear shift console. Often the relay goes bad or gets corroded and the signals won't work properly.

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there are a great variety of relays and hazard switches, it seems to me. i was able to fix mine (same symptom) by replacing the two capacitors in it.

It's an 84 300TD (this would qualify as later model?) so, I'm hoping that it's only the flasher in front of the shifter. Easy fix as I've got the wood trim off for reconditioning anyway.

All the lights light up. They even serve as signal lights if I operate the lever manually.

Thanks for the info.

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

I was just looking at the schematic and it looks like the later cars have a separate flasher. The older ones look to have an integrated switch and flasher. Is that the 250 dollar one?

Has anyone just tried replacing the flasher with a generic 3 terminal unit?

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

afik, the HUGE flasher button that sits to the rear of the shifter on the older (81-77) 123's is not available anywhere but the MB Classic center, and not for sale unless you find one in a junkyard. (or get one of the few I have left that are pulls) and the classic center wants MASSIVE dollars for it...

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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!