Depending on the type of headlights installed on the vehicle, there are two types of headlight beam tilt correction:
- Manual headlight range adjustment - halogen headlights only (only cars for other countries)
- Automatic headlight beam leveling - xenon headlights only
Manual headlight range adjustment - Rest of the world, halogen headlights only
The manual headlight range adjustment system is only fitted to vehicles for other countries with halogen headlights.
NOTE: Headlight range adjustment is not available on North American vehicles with halogen headlights.
The manual system includes the following elements:
- Two electric motors for headlight range adjustment
- Rotary switch for headlight beam adjustment rheostat
When the ignition is in power mode for ignition 6, power is supplied to the lighting control module through the ignition relay in the BJB and the fuse in the CJB. Power is also supplied through the ignition relay in the BJB to the headlamp leveling motor in each headlamp assembly.
Turning the headlight beam adjustment switch generates a different voltage that is sensed by the electric motors. The electric motors respond to the applied voltage and move the headlights to a predetermined position, which corresponds to the voltage applied from the rotary switch. The headlights can be lowered from the unladen position to compensate for changes in vehicle height caused by the load.
The headlight beam tilt adjustment knob has no specific positions that affect vehicle loading. The approximate rotary control position for a given load is shown in the following table:
| Rotary encoder rotation | Car loading |
| 0 | Driver only or driver and passenger in the front seat. |
| 1/4 | Driver and passengers in all seats |
| 1/2 | Maximum Gross Vehicle Weight |
| Full | Maximum rear axle load |
Automatic headlight beam leveling - xenon headlights only
The automatic headlight range adjustment is only fitted to vehicles with xenon headlights. The system is not a dynamic headlight range control system and changes in vehicle tilt due to positive and negative acceleration are not compensated.
Automatic headlight beam leveling provides static, intermittent vertical adjustment of the headlights to minimize glare to other road users when vehicle height changes due to vehicle loading.
The automatic headlight beam leveling is controlled by the headlight beam leveling module, which is located on the bulkhead next to the instrument panel on the pillar «A» from the passenger side.
NOTE: On vehicles with AFS, the headlight beam leveling software is built into the AFS control module.
The headlight beam tilt correction system includes the following elements and receives information from other vehicle systems:
- Front and rear vehicle height sensors
- Two vertical adjustment motors for headlight beam tilt correction
- Headlight range control module (or AFS control module if vehicle is equipped with AFS)
- Ignition in power mode 6
When the ignition is in power mode 6, power is supplied through the ignition relay in the BJB to the lighting control module, headlight range adjustment motors (or AFS motors, if equipped with this system) and to the headlight range correction module (or AFS control module, if available).
When the light control module's rotary switch is turned to position lamps on or headlights on, a message is sent from the lighting control module to the CJB on the LIN bus for the selected function. The CJB then communicates over the high speed CAN bus to the headlight beam throw correction module (or AFS control module, if available) message «lighting on».
Headlight range control module (or AFS control module, if equipped) uses signals from the front and rear height sensors to periodically adjust the headlight height to the optimum position.
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