ODI initially received 21 reports of rear light assembly failure due to a melted electrical connector or housing.Since opening the initial , ODI has received a total of 114 complaints reflecting an ongoing and increasing trend.In each report, one or both rear light assemblies fail completely (i.e., all lights housed within the assembly extinguish, including the stop, tail, and turn signal functions) when the electrical ground connection is compromised as a result of high resistance and subsequent thermal over-heating.According to Mercedes-Benz, the over-heating of the ground wire is caused by corrosion between the connectors in the ground circuit to the tail light.ODI is aware of a total of 5 reports alleging fire including one injury allegation as a result of this issue.Analysis of subject vehicle complaint data indicates an increased likelihood of failure as the vehicles age.As a result of the evidence presented, this investigation has been upgraded to EA13-008.