Levelling control for vehicle headlamp

摘要

The headlamp unit includes main beam, dipped beam, side lights indicator lights and the levelling adjustment servo motor. The beam bulb (2) and the servo motor are connected to the same earth return (19) while the supply feed and signal feed are taken back directly to the control unit. The other lights in the headlamp unit another common earth return. The headlamp levelling is applied when the dipped beam is on. This involves a steady current without transients in the dipped beam earth return feed, allowing an accurate servo adjustment. The switching effects from the other lights do not affect the servo motor setting.