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Dipped beam headlamps/main beam headlamps
The headlamp units are primarily made of plastic and make use of free-form reflectors in order to optimize light distribution.
The transparent plastic cover is made from polycarbonate, which is coated for protection against scratches and cracks.
In the event of damage to the cover the entire headlamp unit needs to be replaced.
The turn signal lamps and side lights are also integrated in the headlamp unit.
For conventional headlamps, adapting the vehicle to conform to country-specific traffic situations (left/right-hand side traffic) during travel is accomplished by affixing punched adhesive strips to specific areas of the headlamp.
Headlamp leveling system
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Headlamp leveling system servo motor
The headlamp leveling system is operated by means of voltage controlled DC motors and is actuated by the headlamp leveling switch.
Each headlamp unit is equipped with a headlamp leveling positioning motor which adjusts the swiveling reflector via an adjusting spindle until the required setting is attained.
A potentiometer inside the headlamp leveling switch is used to adjust a voltage (required value). Following the same principle, the actuator in the motor produces a voltage according to the position of the adjustment spindle (actual value).
The electronic system compares the required value (setting of the switch) with the actual value (adjustment spindle setting). Depending on the voltage difference, the reflector is moved upwards or downwards until the voltages are identical.
Automatic headlamps
The dipped beam headlamps, side lights and license plate lamps are switched on automatically if all of the following conditions are satisfied:
- Ignition switch in the "II" or "III" position
- Light switch in the "AUTO" position
- Detected ambient light conditions below a stored threshold value
The dipped beam, the side lights and the license plate lamps are switched on or off by the generic electronic module (GEM) according to the input signals of the combined rain sensor/light sensor. This takes place in the generic electronic module (GEM) by activating the dipped beam relay and the automatic headlamps relay (side lights/license plate lamps).
Headlamp switch-off delay
The headlamp switch-off delay function uses the dipped beam headlamps to illuminate the area surrounding the vehicle. The side lights and the license plate lamps are also switched on.
The function is activated by switching on the main beam headlamps with the ignition key removed from the lock.
The headlamp switch-off delay function is active for 30 seconds and then switches off automatically.
When a door or the tailgate is open, the switch-off time is extended to 180 seconds. After the last door has been closed, the switch-off time is reset to 30 seconds.
The headlamp switch-off delay can be deactivated prematurely by operating the high beam lever again or by switching on the ignition.
The switch-off time is set at the factory and can be reprogrammed to a maximum of 180 seconds using WDS.
Combined rain sensor/light sensor
The combined rain sensor/light sensor (1) is attached to the windshield, near to the interior rear view mirror.
If both the ambient light sensor and the front light sensor detect a sudden reduction in light intensity at the same time, then an algorithm-based calculation is used to determine the fact that the vehicle has entered a tunnel, a multi-storey car park or a long underpass.
In this case, the request for switching on the exterior lighting and the indicator light in the instrument cluster is transmitted to the generic electronic module (GEM.
If the vehicle enters into the shade thrown by a large truck, the two sensors will register different light intensities.. In this case, the algorithm-based calculation will not result in the lights being switched on.
Rear lighting
The rear lamp clusters incorporate all of the rear lighting functions except the license plate lamp and the additional high-mounted stop lamp.
The rear lamp assemblies are replaced as a complete unit during servicing.
The rear lamp assemblies need to be removed in order to change a bulb.
The individual bulb holders and circuits are integrated into the lamp holder.
A compact connector connects the lamp holder to the wiring harness.
On vehicles equipped with a liftgate, the high mounted stoplamp is installed in the center of the liftgate. On vehicles with rear doors it is positioned in the left-hand rear door.
