Back in July, the National Highway Traffic Safety Administration began a preliminary investigation of the Mercedes-Benz C-Class. At the time, the agency had received 21 consumer complaints about taillight failures in those vehicles from the 2008 and 2009 model-years.
According to Detroit News, the investigation has just been expanded to include vehicles from 2010 and 2011 as well. All told, NHTSA has received a whopping 114 complaints about the C-Class.
The degree and manner of the taillight failures varies dramatically in those reports. In some cases, the lights simply stop working; in others, owners report seeing burn marks in the vehicles' trunks. And in at least one case, an owner saw flames coming from the rear lamp connector.
Though the investigation is ongoing, early data points to a problem with the ground connection associated with the taillights. A NHTSA bulletin reports that the ground wire has been found to overheat, and Mercedes-Benz's parent company, Daimler, acknowledges that such overheating stems from corrosion in the connections that link the ground circuit to the taillights.
NHTSA's investigation now includes just under 253,000 Mercedes-Benz vehicles. As of last month, the investigation was still in the Preliminary Evaluation phase (PDF), but should this expanded probe uncover a persistent flaw in C-Class models, NHTSA will move to the next phase, an Engineering Analysis. And if that investigation yields cause for concern, it will, in turn, lead to an official recall.
We'll keep you posted as the probe progresses.