Three problems related to turn signal have been reported for the 2010 Mercedes Benz C300. The most recently reported issues are listed below.
Rear driver side lights not functioning. Found brown wire meeting to circuit board with heat damage to wire and circuitboard at connection. Contact the dealer. Dealers stated recall was done on our vehicle. However this appears to have happened again. Don't know if this happened while the vehicle was in motion. Noticed warning lights indicating bad connection to brake lights and turn signals driver side rear.
The warning system for the rear lights have been going off since purchasing the certified preowned vehicle in June 2014. It was returned the dealer multiple times for the issue and never fixed. While driving at night I smelled something burning and the warning system informed me to check all of my rear lights. There were no lights functioning on the rear of the vehicle while driving. The lights, brake lights, turn signals, and rear fog lamps were all not functioning. When a road side technician checked the vehicle he saw burnt wires and melted plastic on the lighting mount. This occurred during a routine trip from new jersey into philadelphia, PA and included driving over the ben franklin bridge. Once I reach philly I stopped the vehicle and called for assistance. That is when the issue was located. The car was towed to the dealer for repair. No more information has been provided from the dealer yet.
Similar to other complaints that have been filed against mercedes, it seems as though the electrical connection to my rear right light (brake light, running light, turn signal, etc. ) has melted and is no longer operational. The entire light is out and I get warning messages on the dash about the problem. It looks like this is the same problem that everyone else with the same make/model as me are having. Hopefully mercedes recognizes the scale of this flaw in their engineering and sends out a recall sooner than later.