MurderedC300

My 2011 c300 has the LED rear turn signals. I cannot use my right rear turn signal without getting an error message on the dashboard “check right rear turn signal”. The turn signal works fine and blinks normal, but I get the message and the fast blink on my dash.

The car has already had the recall done for that tail lamp melting issue, so I don’t know what might be causing this. It is a nusance that I would really like to address. Does anyone know what I might do to fix this? The dealer said it’s not covered under my extended warranty and offered an astronomical hourly rate to “diagnose” the issue, stating that they cannot guarantee it will be fixed. So I’m stuck, what can I do?

In 2013 the car was rear-ended while I was stopped at a red light. The deck lid and rear bumper cover had to be replaced and the work was done at a certified Mercedes repair facility. When I open the passenger’s side access panel in the trunk it is very dusty and dirty in there, and seems to be moist, as if water and debris is getting in there somehow. Is there a weather seal on the back of the headlight that could be letting water in, causing a corrosion issue with the wiring and grounding?

Any thoughts would be helpful, the message and fast interior blinking turn signal is driving me nuts!

Thanks

ItalianJoe1

Yes water in the light could be a problem

Are you sure it has the correct type of bulbs in the light? You can use a bulb without the resistor, which will work but still give bulb out warnings.

MurderedC300

The turn signal worked fine for years, then started with this issue intermittently where I could turn the car off and back on to reset it. Now it has become nearly constant when ever I use the right turn signal for the first time. Randomly it will not throw the error message and work properly, but more times than not it causes the error message.

The actual led turn signal always works when I check it outside of the vehicle, yet I get the the error message.

HBguy

I got the message on mine and it looked fine. Dealer told me to check the bulbs. Long story short, it can look fine but a bulb can be out. Did you check every single bulb?

Also, take the whole housing out and clean it up. It's possible you don't have OEM parts, and got knock offs in there. Most dealers outsource to body shops and most bodyshops use 'refurbished' (junk yard) parts if/when they can. It's possible one was installed not knowing it wasn't OEM.

MurderedC300

is it possible to have a single bulb out on the turn signal? Without removing it and looking at it flashing, it appears to be a strip of many small LED bulbs.

If it turn out that a non oem part was used, what should I do then?

HBguy

i thought mine were leds also until i took it out. I also compared the lights on the left and right and it did look the same.

it was a long time ago when i had it but i remember that once i looked at each bulb, i fixed it quick with a new bulb....it really was as simple as a car 40 years older would be. But if your bulb housing is dirty, take it out and clean the whole area. Thst 'dirty' turms to corrosion, especially eith moisture. Forget the bulbs (easiest fix on a car), you dont want to need to replace wiring from corroded terminals.

HBguy

For what its worth, the dealer had told me that "another bulb takes its place" when one goes bad. I thought that was absurd until i saw that the lights on left and right looked the same and i did find a bad bulb. Im 90% sure it was turn signal, not brake.

Mercopen

Hi, I had the problem yesterday with my rear turn signal led not working. I checked the connection wires and noticed some corrosion on one wire. Got rid of that corrosion (Temporary fix) and the problem was solved. I'm thinking of terminating that wire and securing it properly and then covering it with silicone.

ItalianJoe1

Early 204s had a recall for updated taillight carriers, not sure if yours have been replaced, might be worth checking.

idstumped

Re-tested right turn signal problem and got the same results as first testing:
Right turn signal on- no power at harness no power at SAM all pins
Left turn signal on- power at harness power at SAM one pin
Has ongoing rear SAM fault code same as first testing.
Info cluster warns of right turn signal as if the bulb is burnt
SAM looks fine with no water damage detected. I opened it to check PC board.
Code reader shows right turn signal working at rear SAM in real time testing.
Should I be testing elsewhere?

gbmrob

Thanks guys! The right turn signal ended up just needing a brand new reset through the system files. Everything is back to normal

WillieS

How is a "brand new reset through the system files completed"? The Dealer or can it be done at home ?
I just bought a 2021 E350 and this same warning started popping up on week two and pop up about every 3 - 5 days. Signal lamp blinks fine on the outside, but inside the signal indicator blinks fast.

WillieS

How is a "brand new reset through the system files completed"? The Dealer or can it be done at home ?
I just bought a 2021 E350 and this same warning started popping up on week two and pop up about every 3 - 5 days. Signal lamp blinks fine on the outside, but inside the signal indicator blinks fast.

mssishere

Same thing happened to my C200 2012 last night and Im assuming theres no solution on how to reset it 💀