The Mercedes tail lights are controlled by the rear Signal Acquisition Module. The SAM can be found at the left side of the trunk and are generally available in aftermarket stores. Hence a diagnostic scanner may be required to check the codes in the system. If this is unavailable, home testing can be done by testing the wiring. If the wiring is fine, the problem is probably with the module. In case the tail lights were working after the SAM was replaced but stopped after the lights were tested, this would be an indication of short circuiting. The driver for tail lights inside the module could have blown.
Mercedes acknowledged the issue. In its report, the company stated that 23,000 warranty claims tied to the brand have something to do with Mercedes tail light problems.
The scrutiny from the Feds came after 402 complaints were filed to both the US National Traffic Safety Administration (NHTSA) and the German automaker regarding Mercedes tail light problems. The figures include five cases of fires and one injury based on reports.
The investigation regarding the Mercedes tail light problems covers around 253,000 cars of the brand. Year 2008 up to 2011 C-Class models are the subjects of the probe.