Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Rear window lift mechanisms
The rear side windows are operated by motors in the doors. The switches for operating the windows are in the door panels. The windows can also be operated from the driver's door module (DDM).
The function is controlled by five relays on the central electronic module (CEM). Depending on whether the control switch is moved up or down, the relays are activated to carry out the requested operation.
Two relays guide the window up on the right and left-hand sides. Two different relays guide the window down. A further relay controls the power supply.
When operated from the driver's position, information is transmitted via the controller area network (CAN) from the driver's door module (DDM) to the central electronic module (CEM) which sends out signals to the relays.
There are diagnostics for the relays for the rear window lift mechanisms.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.