Models from year 2007 and beyond from Mercedes, come equipped with a Body Control Module (BCM) that acts as a controller for signals to the wiper and washer the rear fog lamps, tail lamps, the automatic light control system, the day operating lights or the DRL, indicators for seat belt and parking brakes, window delay time, door unlocking or locking security system and the control for front and rear A/C. If there are problems with any of them and straightforward diagnostics do not shed light on the problem, it can be best to seek the help of the dealer service department or compulsorily a professional auto repair work station. This may be done by opening the bonnet of the car and unscrewing the mounting bolts of the assembly; however, in models that are of 2009 and below, three screws are required to be loosened. Subsequently take off the headlight mounting bolts and then, gently position this assembly out of the bumper covers and then, disconnect the wiring that belongs to the headlight assembly. The installation procedure is carried out in a reverse manner to the one used in the removal process, and the headlight adjustment should be checked at the end of the process.