Variable light distribution (depending on the national-market version)
The variable light distribution enables a broader illumination of the roadway ahead of the vehicle. With the exception of the light distribution on a country road, the light distribution is determined by a brightness control of the LEDs and specific headlight adjustments (which means rotating the headlights to the side and in height).
Depending on the request from the footwell module (FRM) or the Body Domain Controller (BDC), the headlight driver module controls the swivel module using the stepper motors and therefore controls the light distribution. The transitions between the individual light distributions are smooth.
In conjunction with the "Adaptive Headlight" optional equipment, the following variable light distribution are available:
- Engine start
In switch position A (light switch in the switch position for automatic driving lights control) and terminal 15 ON, both headlights execute a reference run. That means: Both swivel modules are moved down slightly and then to the desired position (visible when the vehicle is parked in front of a wall: The light cone moves down and then back up. Briefly to the side and then back again). The desired position depends on the load status of the vehicle.
When the engine is started, the headlight driver module initially controls the city light distribution.
- City light distribution
The city light distribution enables a broader illumination of the left roadway at low speeds. The left headlight is moved approx. 7° outward and approx. 0.7° downward. The city light distribution is activated from engine start to a driving speed of approx. 50 km/h.
- Country road light distribution
The country road light distribution is the same as the standard low-beam headlights. For example, at a driving speed above approx. 50 km/h, the city light distribution is changed to the country road light distribution. At a driving speed less than approx. 50 km/h, the footwell module (FRM) or the Body Domain Controller (BDC) switches the light distribution back to the city setting. The country road light distribution represents the basic setting for the headlights. The basic setting is assumed when there are faults in the complete light distribution system.
- Motorway light distribution
The motorway light distribution increases the range of the driving light. The left headlight is moved approx. 3.5° to the left and approx. 0.25° downward. The right headlight is moved approx. 0.2° upward. If the car is driven at over 110 km/h for more than 30 seconds or if the speed exceeds 140 km/h, the footwell module (FRM) or the Body Domain Controller (BDC) switches the corresponding stages of the motorway light distribution depending on the driving speed. If the vehicle speed drops below 110 km/h, the headlights are gradually reset, depending on the driving speed. This takes places in stages (110 km/h - 100 km/h - 90 km/h - 80 km/h). The country road light distribution is activated again at 80 km/h and below.
- Fog light distribution
The fog light distribution is activated when the fog lights are switched on. The fog light distribution can be combined with the city light distribution and the country road light distribution. Up to a driving speed of approximately 70 km/h, the left headlight is moved approximately 4.5° to the left and approximately 0.7° downward. Beginning at a driving speed over approximately 70 km/h the left headlight moves to the left approximately 3.5° and lowered. If the high beam headlights are switched on while the fog light distribution is active, the headlight moves to the basic setting, i.e. to the country road light distribution.
The following graphic shows an example of possible light distributions.
| Item | Explanation |
|---|---|
| 1 | City light distribution |
| 2 | Tourist light light distribution |
| 3 | Country road light distribution (also the basic setting of the headlights) |
| 4 | Motorway light distribution |
In the event of a system fault, the footwell module (FRM) or the Body Domain Controller (BDC) prompts a Check Control message. In addition, the footwell module (FRM) or the Body Domain Controller (BDC) switches the system off as follows:
- If the stepper motors are still functional, the headlights are returned to the straight-ahead position. The headlights are no longer moved towards bends in the road.
- If it is no longer possible for a headlight to be moved back to the straight-ahead position, the headlight is lowered (by the stepper motors for automatic headlight beam throw adjustment). This prevents dazzling of oncoming traffic.