My 2012 CLS550 4 Matic has a weird problem.
1. When you turn on the blinkers (left or right) the interior lights on the dash flashes a double speed and I get a warning that the corresponding side front signal light is out. But the signal light on the exterior of the car is working fine. All of them on the exterior are working fine.
2. If I don't start the car and just have it in Key On Engin Off the turn signals work fine. Interior and exterior lights work and blink at the proper rate and no code comes up. No issues at all. Start the car and it is back to being a problem.
3. In this car all the exterior lights with the exception of the backup light are LED. There are no bulbs in the standard sence. The turn signal lights in the front is a cluster of LEDs and all appear to be working and illuminating to the sale brightness
A side note this happened about 1 year ago along with a host of other warning lights. The key warning was the Auxiliary battery needed replacement (a small battery under the dash) I replaced it and all the problems went away including the issue with the turn signals. I pulled the AUX battery out and tested it and it was fine but a new one is $20 so I put a new one in any way.
I have tested all the fuses in all the fuse boxes. I can not find anything on this out on the web.
My local mechanic will not touch this problem he said that I need to take it to someone that has a Star diagnostic tool. This means the Merc Specialty shop or the Dealer. Or if someone has a Star Diagnostic tool around NE that they want to sell or that can read the codes for my car (for a fee of course).
I am hoping one of you out there knows the answer to this. I don't mind spending $$$ I just don't want to waste $$$ as the ammo for the Merc parts cannon is a bit pricey.
Any help would be greatly appreciated.
I do recall that on some Mercedes the turn signals will not work unless you manually clear the code.
Also be mindful of what the turn signal actually is. They will substitute a fog light or other bulb for the turn signal, the fast flash is to let you know that there is a problem.
Pete. (l33t FS) said:
I do recall that on some Mercedes the turn signals will not work unless you manually clear the code.
Also be mindful of what the turn signal actually is. They will substitute a fog light or other bulb for the turn signal, the fast flash is to let you know that there is a problem.
Thanks, I will look into that as I have read somewhere about them swapping lights as well. Time to open the owner's manual and make sure that the signal lights are flashing and it is not the yellow running lights or something. The problem is it is both front lights that are being the issue so I can not look at it from one side to the other.
Thanks!!!
Turn on the 4way flashers and compare side to side.
wae
PowerDork
2/27/22 6:56 p.m.
In reply to Streetwiseguy :
Knowing what I know about the boys in Stuttgart, they probably have a completely separate computer module for each of the left signal, right signal, and the four way flashers.
Just sort of kidding.
In reply to wae :
The bulbs should be the same, though. Eliminates a burned bulb, and allows a comparison side to side.
And yes, no question it will be stupidly wired.
Dang this if anytime is justification that you need to buy a Mercedes SDS copy.
yupididit said:
Dang this if anytime is justification that you need to buy a Mercedes SDS copy.
Think it will happen now I was putting it off.
wae said:
In reply to Streetwiseguy :
Knowing what I know about the boys in Stuttgart, they probably have a completely separate computer module for each of the left signal, right signal, and the four way flashers.
Just sort of kidding.
Tried the 4 way and they work fine.
Another data point. The push button start has been a little flaky ever since I had the car. Sometimes it would just not work. So you pull the button out and start it with the key. What I learned is if I start it with the key everything works fine. Use the button and I have the signal weirdness. So I assume it points to the button as being the problem.
I would see if I could take the button apart and clean the contacts. Otherwise it looks like a replacement is like $50 from FCP Euro.
Thanks for the info!!!! I was fearful that it was going to be a lot more and then a possible programming of it to the car. I am not sure how to take the button apart. I will have to look at it closer. Thanks!!!!
It made a liner out of me. The problem came back with the key but it is much more intermittent. Put the push button start back in and now it is just an intermittent problem. Happening every 2nd or third time I use the signals.
On our R class the rear brake lights would heat up the bulb holder and cause them to loose connection. Maybe something similar is going on.
