mgzych

Have searched turn signal threads, but I think my problem is different.

2004 E500. On occasion, I receive warning of right front turn signal malfunction. It coincides with double-time flashing of turn signal indicator on dash. However, all turn signals on the exterior seem to be working just fine.

I suppose I'm fortunate that the turn signals actually work, but the fast clicking and the repeated malfunction warnings are aggravating.

Any thoughts for a fix?

Thanks,
Mark

whoover

Are you sure the correct bulbs are flashing? The car will switch to a nearby bulb if a signal bulb is out. If all else fails, replace all four signal bulbs.

Ausmbtech

Have you checked the indicators in the mirrors as well?

MercFiveHundred

I had that problem recently too. The turn signal was actually out, but as i drove to my destination, it started working again...???? I hate these cars...sometimes.

mgzych

I'll double-check the mirror signal.

I'm intrigued by the automatic bulb-switching "feature". How can I tell whether the correct lamp is flashing or its "imposter"?

Thanks,
Mark

mleskovar

Replace the right front turn signal. The message is activated by a change in resistance from the bulb. Sometimes the bulb still glows but the filament is actually broken and just touching so it still works but the resistance is high enough to trip the warning message.

whoover

When you get a fast blink, compare the bulb that is flashing to the one that flashes on the other side. If it's in a different position, replace the bulb in that position on the bad side. Actually, always replace them in pairs anyway.

MercFiveHundred

This has been happening more frequently to me. The light does actually stop working when the malfunction message shows and does go back to working after a bit of time (checked on the reflection on the black car in front of me). It's goes off on random times, and works most of the time. I havent replaced the bulbs yet, but i really dont think that is the problem. I have done the fix (DTB) when the circiut goes completely out. So it's on the makeshift new circiut line. This was done about a year ago. Changed the right side also about 2 months ago. Simple things aren't simple anymore.

mgzych

Thanks for the feedback!

whoover: I checked the bulbs based on your response and even when I'm receiving the malfunction message, bulbs on both sides in all positions seem to function properly.

However, I did note that at one of the positions (I don't remember now whether it was the mirror or the front-right signal) the color of one side is colored a paler orange than the other, perhaps an indication that one of the bulbs was replaced at some time in the past without replacing the opposite side.

mleskovar: If I just go ahead and replace the lamp (or pair of lamps), is it safe to assume that the malfunction message's designation of "Front Right" (or "Right Front"?) definitely refers to the the signal at the front bumper light cluster versus, perhaps, the mirror signal?

Also, having read a number of other posts, it sounds to me like the lighting system in MB's are somewhat more complicated than other vehicles. Will the task of replacing the lamp be comparable to, say, replacing the headlight lamp in my Acura (disconnect wiring harness, 1/4 turn, and slide bulb out of housing) or will it involve more?

Thanks, again...

-Mark

whoover

Replacing these bulbs is easy. It's in the manual. Much easier than changing a headlight. They're so cheap, I'd just replace all four.

Turn signal bulbs can develop intermittant filament problems. Since they're not on continuously, the filament sometimes won't get hot enough to just burn through. A crack will increase resistance and cause all kinds of occasional problems. You guys may have something more complicated going on than a bad bulb, but for a few bucks and a few minutes you can eliminate the most likely cause and be sure.

mleskovar

My experience is that the message points out the offending bulb location.
Either turn, headlight, marker (side of fender), fog, stop, rear etc. Also, if the wrong bulb value (watts) is replaced it can trip the warning as well. The warning is tripped by the resistance value of the filament and a higher/lower watt lamp will have a different resistance than the standard one. I was having a problem with the rear lights after about two years of owning the car. Intermittent failure messages and bulbs burning out. They replaced the whole bulb carrier assembly and a rear SAM module and it went away. Clean the socket contacts as well to ensure good contacts (corrosion can cause intermittent problems as well).

KarlBenz

I believe you car is experiencing the same problem that existed with the W203 a complete socket and minor wiring change solves all this and can be easily performed by dealer or a knowledgable person

MercFiveHundred

This is already performed on both sides of my car. The light IS the front left bulb. NOT the side marker. I've swapped both bulbs and STILL same issue. I think the wiring change that KarlBenz is referring to may need to be done AGAIN in my car. Not worth the time to have it break again. I'll live with it.

Saprissa

I just started getting that on my CL203 (C320 Sport Coupe / 2003).
I get the error on the display saying it's the Right Mirror Turn Signal. I get the quick fast-blink, but every single bulb is blinking correctly. So maybe the filament is broken but still touching. How easy is it to change out the bulbs in the side-mirror assemblies ?

So lately, I've just been clearing the display error by pressing on the steering wheel menu button. But....
get this... when I do a one touch roll-down or roll-up of the passenger window, the Right Mirror Turn Signal error message pops back up on the display ?

Is this all triggered by the same module, so maybe it's a module problem ???
I have automatic folding side-mirrors (Euro version), but no power seats. So I don't know if that's a problem with the Door Module or not. Any ideas ??

Carlos

Saprissa@aol.com

mleskovar

Don't know if it's all controlled by the same module but it's sure coincidental enough to make you think so.

Saprissa

I'm thinking it is, and I'm calling on Steve (MBenzNL) to chime in for me.
If anyone can fix this, he can !

Here's an added twist: I have automatic power folding mirrors. But I can also fold them in or out by pressing the button on my light-switch console.
When the mirrors are folded in, and I activate the right-turn signal or auto roll-up/down the passenger window. NO error message. NO fast blinking. NO problems. So maybe it could be a loose connection too that gets separated when the mirrors are extended out.

anyway, don't want to mess with something that will cause more damage... so I'll wait to see what Steve tells me, unless somewhere here knows of a true fix.

Thanks !

Carlos

Saprissa@aol.com

MercFiveHundred

Left turn signal stopped working now. Great!

Moviela

My mirror covers are equipped with a string of LED's. They are supposed to last forever, but my experience is that high light output LED's often expire earlier than expected. The LED's are connected in series, so if one is open, they all stop glowing. I have not, however, had any problem with the LED assemblies. They are easy to remove, once you have the secret of how to remove the cover mastered.

I have had a few problems with the wiring in the mirror. I believe the harness design for the folding mirrors was outsourced to Miss Dunderhead's third grade class. The insulation selected is not suitable for exterior use. It becomes hard as it ages. The wire is quite small as the current requirements of the circuit is small. For flexable wire the number of strands is selectable by the engineer. More of a finer strand is much more flexible and will last longer than larger strands that are less in number. I have replaced the portion of the harness that flexes with wire that has 66 strands, rather than the 8 Mercedes uses. I use AWG 22, which is slightly larger than what Mercedes uses. Here is my source:

http://www.rdswire.com/Documents/FlexWire.pdf

The fast clicking of the sound inside the car and the instrument cluster fast blink is programmed by the front SAM. The exterior lamps flash at the same rate. Back in the mechanical flasher days, an open lamp caused the flasher to blink faster. Mercedes has simulated that effect inside the car, but uses the same timing to blink exterior lamps.

The mirror lamps are actually blinked by the door module. It gets it's marching orders via the CANbus from the front SAM.

Anyone who is having lamp out warnings and no lamp is open, needs to investigate the quality of the connection in the socket. The turn signal lamps use fairly large bayonet sockets, and they can be polished with a Scotch Brite pad cut to fit into the socket. The wedge based lamps, like the city lights are a bit more trouble. An emery board made of thin wood that has fine sand on it can be used to clean the W5W lamp sockets.

Saprissa

Moviela, your explanation makes the most sense to me.
I'm hoping Steve will be here in SoCal at about the same time that I'm in town so he can take a look for me, and see if it requires a door module replacement, or just a wire strand upgrade (as you have done), or simply a loose connection somewhere.

Carlos

Saprissa@aol.com

MercFiveHundred

Mark,

Finally found out what the problem was. Lightly scrape all the contacts from any oxidation and it will work. I don't understand all this oxidation crap. That shouldn't be happening.

nik

Saprissa

Steve will be looking at my turn signal issue on OCT 30th... so hopefully after a little troubleshooting we can figure out what the problem is, and more importantly... the fix !

I'll post details then.

Carlos

Saprissa@aol.com

drb930

Anyone know about the socket and wiring change?
I have a 2002 C230 Coupe and the display says Left Front Turn Signal Malfunction.
Bulb is good and swapped the whole complete socket to the passenger side and it works fine, but the Drivers side still does not work?

Thanks,
Dave

mgzych

Thanks for the update. I haven't revisited the issue because it hasn't happened for quite a while now. -Mark

Rasso01

On my E320/2003 w211 I have the same problem. Have swapped the lamps and sockets. Bought a new socket for the right side. Scrapped the contact. Sprayed the hole sockets with contact cleaner. No succes.
I have figured out that the error never shows up when the car is standing still. The error wil come when I actually run the car. Right in the middle of the curve, the error comes to the display. Hmmmm souns like a wire bad connection or what ??

MercFiveHundred

That's how mine started and then later the malfunction went on when i unlocked the car in the morning. I scraped the contacts with my house key (both on the socket replacement and the headlamp housing) and it went away - but after i turned the car off and then on again. It did come back just recently (its been about 2 months) just one time, but i haven't seen it since. Im beginning to think it was/is just a fluke (aka crazy electrical/computer problem).