Self leveling headlight
 

Hi

What do BMW self leveling headlight on my 02 E53 base itself on? On the surface that your car is sitting on?

Thanks

There is a sensor on the right front control arm.

this applies to self-leveling suspension and by proxy might be applicable to lights...

Kerb

Kerb
Detecting this state prevents the inclination produced when one side of the vehicle rises on an obstacle with one wheel from being balanced out. Compensation would, after driving off the obstacle, lead to a renewed inclination of the vehicle and a renewed intervention.
The Kerb state is detected when the difference in height between the left-hand and right-hand sides of the vehicle > 24 mm.
If the vehicle is loaded or unloaded on an inclination, the control unit analyses the value of the middle of the car between the rear wheels. The value is calculated in the control unit from the changes in height of the right-hand and left-hand spring paths.
If the value of the spring travel or rebound at the calculated centre of the rear axle lies outside the tolerance range of 10 mm, self-levelling is triggered. The left-hand and right-hand sides of the vehicle are raised or lowered in parallel. The difference in height between the two sides remains. As soon as the control unit goes into Drive mode, the Inclination mode is deleted.

Well...I only have rear air suspension, and I do have a sensor on my right front control arm. And I can absolutely confirm that manipulating this sensor DOES effect the headlights. My headlights were out of whack when I got the car, and adjusting this sensor (it can be twisted slightly), was necessary to get it within the calibration range on the Autologic I was using. You can see the headlights move when you twist the sensor.