I've got the same problem as well, haven't check if my wires are burnt.

Anyone know if its a SAM issue, or just caused by the wirings heating up? Or does a malfunctioning SAM cause the wires to heat up which in turn causes in the light to dim?

It also always seems to be the right taillight that has the issue.

 

Well, i had a really good look and I can't even remove the black plug from the circuit board, but when I remove the whole board, as if I was changing the bulb, I can see where heat has started to melt the board and the plastic around the ground wire on the plug has melted to expose the bare wire. All in all, it's a fire hazard so i'll need to replace the whole fitting, including the harness connector to the board.

 

Just checked mine and it's exactly the same as the one pictured. The brown wire all the way to the left is showing signs of heat. I pulled the left side of the connector out a little bit and the taillight got brighter.

I guess I could replace the harness but my question is what caused this? I don't want it to happen again.

I was thinking maybe my license plate LEDs are possibly connected to the brown wire and are causing this? But the other cars with the same problem do not have aftermarket LEDs.

 

This thread should be combined with forums/c-class-w204/465331 Some interesting notes there.

 

Brown is the ground wire.

You can do this yourself if you have the patience to get the pins out of the connector. Or you can just snip them off one by one and strip the wire and buy 7 new pins for like $8. The latter is definitely easier. You just need a wire stripper and a set of needle nose pliers to clamp the pins onto the wire. The former requires a lot of patience and three arms. Be careful not to mangle the pins if you don't have replaements if you go that route.

Remember which goes where. I did them one at a time and inserted them into the corresponding hole on the new connector.

 

I guess I could replace the harness but my question is what caused this? I don't want it to happen again.

It is caused by low quality connections used on the Bulb assembly. the brown wire is earth and that carries the heaviest current. You only need a few ohms resistance on that connection and the pin gets very hot. Enough to melt the plug.
One preventative cure is to clean the male pins on the bulb holder with a pencil eraser and contact cleaner every few months. It is one thing MB should be looking closely at as no one wants a fire in their trunk.

 

If you plan to do the replacement, order plug part number 211-545-03-28 and 4 cables with 2 connectors attached to each part number 000-540-29-05.

It is very important to make good connections from old wire to new one, or you may be adding a source of resistance and heat. I recommend soldering the connections.

As well, the wires are small and difficult to tape. I sealed mine with heat shrinkable tubing from The Source (or Radio Shack) so that they won't short circuit at a later date.

Good luck.

 

I guess I'm not the only one with this problem..

 

Yes, my 2008 w204 had this problem too. One of the pin/wire on the end of both harnesses are corroded and/or burnt. This might be a design flaw if the ground gets too hot.

Also the fact it's on the right hand side is troubling. That's where the emergency kit goes, and it sits up to the wire harness making it even hotter. I'm going to not put anything there and give the plug more air.

 

Just got a letter stating the recall on rear tail lamp bulb carrier.

HHTSA Recall # 14v-177

You are due a refund if you had to pay for this repair.

 

Guys!!! The same thing happened to my wife's 08' W204 and we received the letter showing the VIN number of the affected vehicle. Even though my 2010 W204 wasn't giving any signs of problems, they did the recall on my W204 Sport as well. Recall was done in a couple of hours and car rear taillights are as bright as new now on both vehicles!!! Of course free of charge!