!!!!!+a!!a!!!!a84 300D.

Recently just happend today. So yesterday I changed out all my reverse lights/turn signal lights in the rear. When I went out to test them they worked perfect. Today I was going out for a drive to the store I signal left to pull in the store and my dashboard was emitting a fast blinking turn signal light.
https://speedtest.vet/ https://vidmate.bid/
When I got home I opened up the rear taillight covers both left and right were not working. I checked the bulbs of the turn signal lights they looked good. The parking lights work but the turn signal lights and brake light in rear dont work

Do you still have the old bulbs? If so, put them back in and see if it works normally. If so, then the bulbs are the problem? It is not unheard of to get wrong or inferior made bulbs, albeit both going at the same time is kinda odd. Do they both work ok with the hazard flasher switch??

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Next time you take the bulb holders loose, remove the bulbs and look closely at the metal part inside the bulb sockets that holds the bulb ~ they're made of mild steel and often have a whitish corrosion that's very easy to clean off .

I use and highly recommend LED bulbs *except* for the brake lights because your cruise control won't work with LED bulbs there, the rest are fine .

Let us know what you find ~ some times the copper contacts get dirty / corroded, if so use METAL POLISH and a Q-tip to clean them up, never, use sandpaper or other abrasives ! .

Cleaner/wax works well here too ~ you want shiny copper colored contacts as the base of the bulbs .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

What happens when you use the Emergency Flasher?

When I had the fast blinking turn signal issue using the Emergency Flasher fixed it for a time and eventually it stopped altogether. Replacing the Emergency Flasher Switch fixed the issue.
I believe the issue was caused by my Wife plopping here Purse down on top of the Counsel and on top of the Emergency Flasher Switch.

Not on the Mercedes but on another vehicle I had a tail light bulb that when replaced would last about 3 months and die. I looked into it and found I was using the wrong amperage of bulb. I replace it with the correct slightly more costly bulb and over a year now no issues.

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84 300D, 82 Volvo 244Gl Diesel