The headlamp regulator refers to the situation that the illumination direction of the headlamp deviates from the standard direction under the influence of the trunk load, long-time vibration, high and low road conditions. The function of the light regulator is to adjust the illumination direction of the headlamp from the deviation direction to the standard direction, so as to improve the lighting effect of the headlamp. At present, there are two main modes of light regulator: manual mode is mainly composed of automobile headlamp dimmer motor and manual switch. The headlamp dimmer motor is at the front lamp, the control part is in the cab, and there is a manual switch on the instrument panel, which can be adjusted by the driver according to his own needs; the automatic mode is composed of automobile headlamp dimmer motor, controller and two horizontal sensor groups The horizontal sensors are installed at the front and rear ends of the vehicle body respectively. They mainly detect the height from the vehicle chassis to the ground, and transmit the height difference to the controller in the form of electric signal. After the comparison and calculation, the controller controls the headlamp dimmer motor, thus completing the automatic adjustment function of the headlamp.