The automatic headlight range control ensures the optimum headlight setting and illumination of the road ahead. The headlight range control maintains a constant headlight range however heavily the vehicle is loaded, preventing oncoming traffic from being dazzled. The control function automatically adjusts the headlights' angle of inclination depending on the current vehicle load.
There are two different types of automatic headlight range control system: static and dynamic systems. While static systems can adjust to compensate for the extra weight of the passengers and their luggage, dynamic systems also correct the headlight setting when the vehicle is pulling away, accelerating and braking.
In static systems, the control unit processes information it receives from tilt sensors in addition to signals from the electronic speedometer and the ABS control unit. This enables the system to determine whether the vehicle is stationary or travelling at a constant speed.
Volkswagen's dynamic headlight range control system adjusts to the correct headlight setting in all driving situations. Its control unit also monitors changes in the speed signals as the vehicle accelerates or brakes. Processing these extra signals requires a far more powerful control unit. Its actuator motor also adjusts at a higher speed to correct the headlight range within a fraction of a second. Automatic headlight range adjustment is a legal requirement on vehicles fitted with xenon headlights.