Mercedes-Benz W211 xenon headlight levelling does not work
W211 why does the xenon light stay in the lowered position and the levelling does not work?
The most common cause is the levelling motor behind the headlight unit. It is a stepper motor that finds its home position at start-up by driving to its end position, and a worn motor sticks in the lowered position. Replacing the motor has fixed the fault.
W211 how do you check the condition of the levelling motor?
The motor's two coils are measured with a multimeter from the connector pins, and in a good motor their resistances are the same. In one example the coils of a working motor were 7.2 ohms, while the resistances of the faulty one were 10.8 and 25.4 ohms.
W211 what other than the motor can prevent levelling?
The insulation of the wires inside the headlight unit can crack in the heat, exposing the copper. The wires are repaired or renewed. If the levelling does not work after replacing the light control module, check that the module's wire is attached to the CAN bus connector.