Types, device and principle of operation of the headlight range control

The dipped headlights of a car have an established cut-off line, the position of which is regulated by international rules and standards. This is a conditional line of transition of light into shadow, which should be chosen in such a way as not to blind other participants in the movement. On the other hand, it must provide an acceptable level of road illumination. If the position of the car body changes for some reason, then the position of the cut-off line also changes. In order for the driver to be able to adjust the direction of the dipped beam, i.e. cut-off line and headlight range control is applied.

Purpose of headlight range control

The initially correct headlights are set on an unloaded vehicle with the longitudinal axis in a horizontal position. If the front or rear is loaded (for example, passengers or cargo), then the position of the body changes. An assistant in such a situation is the headlight range control. In Europe, all vehicles from 1999 onwards must be equipped with a similar system.

Types of headlight correctors

Headlight correctors are divided according to the principle of operation into two types:

• forced (manual) action;
• auto.

Manual light adjustment is made by the driver himself from the passenger compartment using various drives. By the type of action, the actuators are divided into:

• mechanical;
• pneumatic;
• hydraulic;
• electromechanical.

Mechanical

The mechanical adjustment of the light beam is not made from the passenger compartment, but directly on the headlight. This is a primitive mechanism based on an adjusting screw. It is usually used in older car models. The level of the light beam is adjusted by turning the screw in one direction or another.

Pneumatic

Pneumatic adjustment is not widely used due to the complexity of the mechanism. It can be adjusted automatically or manually. In the case of manual pneumatic adjustment, the driver must set the n-position switch on the panel. This type is used in conjunction with halogen lighting.

In automatic mode, body position sensors, mechanisms and a system control unit are used. The reflector regulates the air pressure in the lines that are connected to the lighting system.

Гидравлический

The principle of operation is similar to the mechanical one, only in this case the position is adjusted using a special liquid in sealed lines. The driver adjusts the position of the lighting by turning the dial in the passenger compartment. In this case, mechanical work is performed. The system is connected to the main hydraulic cylinder. Turning the wheel increases pressure. The cylinders move, and the mechanism turns the stem and reflectors in the headlights. The tightness of the system allows you to adjust the position of the light in both directions.

The system is considered not very reliable, since over time, tightness is lost at the junction of the cuffs and tubes. Fluid flows out, allowing air to enter the system.

Electromechanical

Electromechanical drive is the most common and popular low beam adjustment option in many vehicles. It is adjusted by the driver's rotation of the wheel with divisions in the passenger compartment on the dashboard. There are usually 4 positions.

The actuator is a geared motor. It consists of an electric motor, an electronic board and a worm gear. The electronic board processes the command, and the electric motor rotates the shaft and stem. The stem changes the position of the reflector.

Automatic headlight adjustment

If the car has an automatic low beam correction system, then the driver does not need to adjust or turn anything himself. Automation is responsible for this. The system usually includes:

• Control block;
• body position sensors;
• executive mechanisms.

Sensors analyze the vehicle's ground clearance. If there are changes, then a signal is sent to the control unit and the actuators adjust the position of the headlights. Often this system is integrated with other body positioning systems.

Also, the automatic system works in a dynamic mode. Lighting, especially xenon lighting, can instantly blind the driver. This can happen with a sharp change in ground clearance on the road, when braking and a sharp forward movement. The dynamic corrector instantly adjusts the light output, preventing the glare from dazzling drivers.

According to regulatory requirements, cars with xenon headlights must have an auto-corrector for low beam.

Corrector installation

If the car does not have such a system, then you can install it yourself. There are various kits on the market (from electromechanical to automatic) at a variety of prices. The main thing is that the device matches the lighting system of your car. If you have special skills and tools, you can install the system yourself.

After installation, you need to adjust and adjust the luminous flux. To do this, you need to draw a special diagram on the wall or shield, on which the points of deflection of the beam are indicated. Each headlight is individually adjustable.

How to check if it works

The body position sensors can be different. For example, the life of potentiometric sensors is 10-15 years. The electromechanical drive can also fail. With automatic adjustment, you can hear the characteristic hum of the adjustment drive when the ignition and dipped beam are turned on. If you do not hear it, then this is a signal of a malfunction.

Also, the performance of the system can be checked by mechanically changing the position of the car body. If the luminous flux changes, then the system is working. The cause of the breakdown may be electrical wiring. In this case, service diagnostics are required.

The headlight range control is an important safety feature. Many drivers do not attach much importance to this. But you need to understand that the wrong or blinding light can lead to sad consequences. This is especially true for vehicles with xenon headlights. Don't put others in danger.