Automatic Headlight Levelling
SécuritéAverage price
300€ - 1500€
Automatic headlight levelling, also known as automatic headlamp height adjustment, is an essential active safety system on modern vehicles. Its primary function is to adjust the tilt of the headlight beam in real-time without driver intervention, ensuring optimal visibility without dazzling other road users. The system continuously analyzes the vehicle's attitude, i.e., its longitudinal tilt. Whether during hard acceleration, heavy braking, or when the vehicle is heavily loaded (full trunk, rear passengers), the attitude changes, thereby altering the natural orientation of the headlights. Without correction, the headlights could either aim too low, reducing the field of vision, or aim too high, dangerously dazzling oncoming drivers. Using sensors located on the front and rear axles, a control unit determines the vehicle's angle and commands small electric motors integrated into the headlight assemblies to adjust the beam height. This device is legally mandatory in Europe for Xenon headlights and has become a standard on most vehicles equipped with advanced lighting technologies such as LEDs or Matrix LEDs.
Benefits
- ✓Enhanced safety by preventing the dazzling of other drivers
- ✓Consistently optimal nighttime visibility regardless of vehicle load
- ✓Total comfort for the driver who does not need to worry about manual adjustment
- ✓Regulatory compliance for powerful lighting systems
Learn more
The automatic headlight range control is a safety feature that is often overlooked yet fundamental for nighttime driving. Integrated into modern lighting systems, it ensures that your headlights illuminate the road optimally under all circumstances, without ever compromising the safety of other road users. This automated system replaces the old manual adjustment thumbwheel, offering unmatched comfort and precision.
How does the automatic headlight range control work?
The operation of this ingenious system relies on a chain of information and actions taking place in just a few milliseconds. Here are the key components:
- Ride height sensors (Level sensors): Placed on the front and rear suspensions, these sensors continuously measure the inclination of the vehicle's chassis. They detect variations due to loading (passengers, luggage), acceleration (the vehicle pitches up), or braking (the vehicle dives).
- Electronic Control Unit (ECU): An electronic control unit centralizes the data sent by the ride height sensors. It compares the vehicle's current inclination to a reference value and calculates the necessary adjustment for headlight height.
- Motorized actuators: Integrated directly into each headlamp assembly, small electric motors receive commands from the ECU. They physically adjust the orientation of the reflector or projector to raise or lower the light beam.
This process is entirely seamless for the driver. As soon as you load your trunk or passengers get into the rear, the system compensates for the lowering of the rear of the vehicle by dipping the headlights to prevent them from illuminating the sky.
A crucial safety element
The importance of the automatic headlight range control must not be underestimated. A poorly adjusted light beam can have two major consequences:
- Glare: If the headlights are aimed too high, they blind the drivers of vehicles you are meeting or following. This glare, even brief, can cause a loss of control or an accident.
- Lack of visibility: If the headlights are aimed too low, the illumination range is significantly reduced. The driver then has less time to react to an obstacle, a pedestrian, or a sharp turn.
By constantly maintaining the ideal range, this system guarantees the best possible visibility for the driver while preserving the safety of others. It is a pillar of active nighttime safety.
Connection with modern lighting technologies
The automatic headlight range control is inseparable from high-performance headlights. European regulations (ECE R48) mandate its presence on all vehicles equipped with light sources whose luminous flux exceeds 2,000 lumens, which is the case for virtually all Xenon headlights. This requirement was established because the high intensity of these headlights makes glare particularly dangerous.
Today, even if some basic LED headlights do not reach this threshold, the automatic leveling system has become standard on most vehicles equipped with Full LED, Matrix LED, or adaptive headlights. For these advanced systems that modulate the beam in real-time, a perfect and constant reference ride height is essential for their proper operation.
System failure and maintenance
Although reliable, the automatic headlight range control is not immune to failure. A breakdown is often manifested by an error message on the dashboard and the headlights moving to "safe" mode, i.e., positioned at their lowest setting to avoid any risk of glare. Causes can include a defective ride height sensor (often exposed to road debris underneath the car) or a burned-out motor within the headlight assembly. During the technical inspection (MOT/roadworthiness test), the proper functioning of the headlight height adjustment is checked. A faulty automatic system can therefore be grounds for a re-test.
Associated equipment
Automatic High Beams
Automatic high beams, also known as High Beam Assist, are an Advanced Driver Assistance System (ADAS) that autonomously manages the activation and deactivation of the high beam headlights. The system relies on a front-facing camera, usually located behind the windshield near the rearview mirror, to continuously analyze lighting and traffic conditions. It detects the headlights of oncoming vehicles, the taillights of vehicles ahead, and the street lighting of populated areas. When the road is dark and clear, the system automatically engages the high beams to provide maximum visibility for the driver. Upon approaching another road user, it instantly switches back to low beams to prevent dazzling. This intelligent technology significantly improves safety by maximizing the use of high beams, which drivers tend to underutilize. By reducing the mental workload associated with this constant adjustment, it allows the driver to remain more focused on their trajectory and the potential hazards of nighttime driving. This system is often the first step toward more advanced technologies such as matrix headlights (Matrix LED).
Matrix LED Headlights
Matrix LED headlights represent a major technological breakthrough in automotive lighting and active safety. Unlike traditional or even standard Full LED headlights, this technology uses a matrix of dozens, or even hundreds, of individually controlled light-emitting diodes (LEDs). The system works in tandem with a camera, usually located behind the interior rearview mirror, which constantly scans the road. When it detects a vehicle (approaching from the opposite direction or traveling ahead in the same direction), the system's processor analyzes its position and trajectory in real time. It then selectively and ultra-fast switches off the specific LED segments that would otherwise directly illuminate that vehicle. This creates a sort of moving 'shadow tunnel' around other road users, preventing them from being dazzled. Meanwhile, the rest of the road, particularly the roadside and the area far ahead, remains perfectly illuminated by the high beams. The driver thus benefits from maximum visibility, equivalent to that of high beams, without ever having to manually deactivate them, significantly improving safety and nighttime driving comfort.
Adaptive Headlights
Adaptive headlights, also known as adaptive lighting or AFS (Adaptive Front-lighting System), represent a major breakthrough in automotive lighting technology. Unlike traditional headlights that project a fixed light beam, adaptive headlights dynamically adjust the orientation, shape, and intensity of the beam based on vehicle speed, steering wheel angle, and traffic conditions. Using sensors and an electronic control unit, the lighting modules can swivel horizontally to illuminate the inside of curves, or vertically to compensate for vehicle pitch variations. The most sophisticated systems, such as Matrix LED or Pixel headlights, go further by using dozens of individually controlled light-emitting diodes (LEDs). They can thus create dynamic 'shadow zones' to avoid dazzling oncoming drivers or those ahead, while keeping high beams activated on the rest of the road. This technology significantly improves night vision, anticipates potential hazards in curves, and increases overall safety for all road users.
Headlight height adjustment
Headlight height adjustment is an essential safety feature used to adjust the vertical angle of the low beam light pattern. Its primary objective is twofold: to ensure optimal road visibility for the driver and to prevent dazzling other road users, whether oncoming or ahead of the vehicle. Incorrect adjustment, often caused by a heavy load in the trunk or on the rear seat, can cause the headlights to point too high, reducing the effective illumination range on the road and creating a hazard for others. Conversely, headlights adjusted too low dangerously limit the night-time field of vision. There are two main systems: manual adjustment, controlled by a thumbwheel on the dashboard (usually graduated from 0 to 3 or 4), and automatic adjustment, known as headlight range control. The latter uses sensors on the axles to adjust the headlight level in real time, without driver intervention, depending on vehicle load, acceleration, and braking. Automatic headlight range control is also mandatory on vehicles equipped with Xenon headlights or powerful LED systems to guarantee maximum safety under all circumstances.