The official notice
Defect
On certain vehicles, water could leak into the trunk causing the signal acquisition and actuation module (SAM) to short circuit. If this happens, the tail lamps may not work, the rearview camera may not work, and/or the rear seat backrests could fold on their own.
Safety Risk
A short circuit could create the risk of a fire. Tail lamps that don't work could make a vehicle less visible, and cause a following driver not to recognize that the vehicle is braking or intends to turn. A rearview camera image that does not display correctly could reduce a driver's ability to see behind the vehicle while backing up. These issues could increase the risk of a crash. Additionally, a backrest that folds on its own could increase the risk of injury.
Remedy
Mercedes-Benz will notify owners by mail and instruct you to take your vehicle to a dealership to install a cover over the signal acquisition and actuation module (SAM).