Headlamp Alignment Switch: Description and Operation

Headlamp Levelling Switch (282)






Main Task
Headlamp beam adjustment on cars without automatic headlamp levelling.

Type
On cars with manual headlamp levelling, the knob has three positions to the left of the headlamp position. These positions are used to regulate beam length. They are resistive multiplexing, which leads to an additional number of resistors in this variant. Five resistors are internally coupled between +15 and ground. The switch knob straight up in the headlamp position gives normal beam length. High voltage is taken out in this position between the fourth and fifth resistor calculated from ground. Each step the beam length is to be moved closer to the car, voltage is taken out closer to ground, thereby sinking. The light switch also has LEDs for illuminating symbols and the knob.

Connection









Headlamp levelling requires one pin for +15 and one for the output to the two headlamp levelling motors. The LEDs are grounded internally and are supplied with PWM from BCM.






Switch, left-hand headlamp levelling motor

Diagram:

Switch, right-hand headlamp levelling motor