Headlamp range control (HRC), function - GF82.10-P-0001A

MODEL 129, 140, 202, 208, 210 with CODE (612b) Xenon headlamp unit 

Electric headlamp range adjustment is required by law for vehicles with xenon headlamps to prevent dazzling oncoming traffic. The headlamp range adjustment automatically keeps the inclination angle of the low beams within the legally defined limit regardless of how the vehicle is loaded.

The front and rear axle sensors for the headlamp range adjustment sense any change in the vehicle level for the headlamp range adjustment control module. The control module compares the signals from the sensors with the headlamp adjustment and, if necessary, actuates the headlamp range adjustment motors in the headlamps to correct the angle of inclination.

Correction of the angle of inclination is accomplished only when the signals for the changed vehicle level are present at the control module for a certain time. This prevents correction for short term changes in the level, e.g. suspension compression on rough roads. The ignition and low beam headlamps must be switched on for the electric headlamp range adjustment to operate.

On model 129 with adaptive damping system (ADS) the headlamp range adjustment control module senses the changes in the vehicle level from the signals from the level control sensors on the front and rear axles.