LR3/Disco 3
the 'AUTO' position and a lights on request signal from the light sensor.
HEADLAMP LEVELLING
Headlamp levelling provides for the adjustment of the vertical aim of the headlamps. The levelling system is primarily
required to minimise glare to other road users when a heavy load is in the rear of the vehicle.
Three systems of headlamp levelling are available; manual, static and dynamic.
Manual Headlamp Levelling
Manual headlamp levelling is only available on vehicles with halogen headlamps and coil spring suspension.
The manual system comprises the following components:
Two headlamp levelling motors
Headlamp levelling rheostat rotary control.
When the ignition switch is in the ignition position (II), power is supplied to the lighting control switch via the ignition relay
in the battery junction box and to the headlamp levelling motor in each headlamp assembly via the CJB. When the lighting
control rotary switch is moved to the side lamp or headlamp position, the supply from the ignition relay is passed to the
levelling rotary control.
Movement of the levelling rotary control produces a variable voltage output, which is sensed by the motors. The motors
react to the supplied voltage and move the headlamp to the requested position which relates to the supplied voltage from
the levelling rotary control.
The headlamps can only be lowered from their unladen position to compensate for changes in vehicle attitude due to
loading.
Vehicle Headlamp Levelling
Vehicle headlamp levelling is only available on vehicles with air suspension.
Vehicle headlamp levelling is performed by the air suspension system and the air suspension control module. The
suspension system constantly monitors the vehicle attitude and adjusts the height of the front and/or rear of the vehicle
accordingly. This maintains the correct vehicle attitude and consequently maintains the correct headlamp beam
alignment.
The vehicle levelling system is fully automatic, therefore the lighting control switch does not have the manual levelling
rotary control.
Dynamic Headlamp Levelling (Air Suspension)
Dynamic headlamp levelling is only available on vehicles with the AFS system and air suspension.
The dynamic headlamp levelling adjusts the vertical alignment of the headlamps as a rapid response to changes in
vehicle attitude due to acceleration or braking.
The dynamic system is fully automatic, therefore the lighting control switch does not have the manual levelling rotary
control.
NOTE :
The dynamic system comprises the following components:
Two headlamp levelling motors
AFS control module
Engine running signal from engine control module
Vehicle speed information from ABS module
The AFS system also operates in conjunction with the vehicle levelling system as described previously.
