These vehicles are equipped with the Central Body Electronic (ZKE-V) system were every individual system is linked with a central control module for easy and effective diagnostic checking. This control module is used for controlling the windshield wipers and washer, central locking and anti theft system, power windows, interior light, alarm system, and electronic consumer sleep mode. If a freon leak is suspected, then diagnosis should be done by a dealer service department or an automotive repair shop as special diagnosing equipment are used. In the case of window switches, there is a process where the regulator is first removed, the switch screws are then undone in order to pull the motor away from the regulator, after which the motor is fixed to the regulator where it secures after the screws have been tightened then finally the assembly is reinstalled. In the case with coupe front window motors, its removal, as well as its installation means that the regulator will have to be detached from the door and this is best handled by the BMW dealer. By using a plastic wedge for the coupe side window motor, the r4 reducer and the nut of the link rod are removed, the link rod shield is pulled off with a clique, and the motor cover that incorporates a clip on the center pin and an expanding rivet is removed. The two mounting bolts can then be slackened and the motor with the bracket can then be pulled out, the wiring connector can then be disconnected as the motor is pulled out. If required, the motor can be unbolted from the bracket by unscrewing two screws, and as in the process of construction, it is bolted backwards, also ensuring that the black plastic cap at the link rod is facing upwards. The electric window system contains the General Module (GM-V) which can be found at behind the passenger side glove box; This can be removed by taking out the glove box and then releasing the retaining clips to pull down the module, then disconnect any wiring connector(s) before removing the module from the car.