LR3/Disco 3
The AFS xenon headlamp construction is similar to the non-AFS xenon headlamp assembly. The AFS assembly contains
an additional carrier frame which provides the location for the AFS components. The remaining lamps are as described
previously for the Xenon headlamp assembly. The functionality of the static bending lamp on the AFS headlamp is
different from the functionality of the cornering lamp on the xenon headlamp.
The carrier frame has a radial bearing at the top and a thrust washer at the bottom which provide the horizontal pivot
points for the xenon projector module. The lamp module lower pivot has a splined end which locates in the mating splines
of the AFS horizontal actuator motor. The carrier frame is suspended on two flexible mountings at the top which provide
for the vertical pivot points for the xenon projector module which allow for the vertical adjustment of the projector module.
The bottom of the carrier frame is attached to the AFS vertical actuator motor.
The AFS actuator motors are dc motors which are driven by a power output from the AFS control module. The AFS
control module also provides the earth path for the motor.
The actuators contain a potentiometer which is connected via wires with gold plated connector pins to the AFS control
module. The two wires to each actuator provide a feedback signal to the AFS control module to give the precise position
of the xenon projector module.
The AFS control module receives front and rear suspension height data to provide dynamic headlamp levelling
adjustment via the vertical actuator motor. The AFS control module also receives vehicle speed signals from the ABS
module to adjust the projector module vertically to increase the beam range as the vehicle speed increases.
Initialisation Procedure
When the AFS control module receives an ignition on signal, the control module performs the initialisation procedure
which ensures that the headlamps are correctly aligned on both their vertical and horizontal axes.
The headlamp levelling initialisation takes less than 3 seconds to complete. The headlamp levelling motors are powered
from their current position, which can be either the upper or lower limit or somewhere in between, to their lower position
and then back to the 0 degrees position.
The AFS swivel initialisation starts less than 1 second after the headlamp levelling initialisation is activated to ensure that
the headlamps are at or below the 0 degree position in the vertical axis, thus preventing glare to oncoming vehicles. The
AFS swivel initialisation is completed in less than 2.5 seconds. The LH and RH AFS actuator motors are powered from
the 0 degree position to their fully inboard position, then to their fully outboard position and then back to the 0 degree
position.
Failure Mode
In the event of a failure of the AFS system, a warning indicator in the instrument cluster is illuminated to warn the driver.
The AFS warning indicator illuminates when the ignition switch is in the ignition position (II) and will illuminate
continuously until the fault is rectified. The AFS warning indicator will also be illuminated if a failure of the steering angle
sensor or the vehicle speed signal is detected.
Illumination of the AFS warning indicator does not necessarily mean that there is a fault with the AFS system. The fault
may be caused by a failure of another system preventing the AFS system operating correctly.
The AFS control module performs a diagnostic routine every time AFS is requested. If any fault is found, the AFS control
module will suspend the operation of the AFS function.
If the AFS system has failed with the xenon projector module in a position other than the correct straight ahead position,
the AFS control module will attempt to drive the xenon projector module to the zero (straight ahead) position. If this is not
possible, the AFS control module will lower the projector module using the levelling actuator motors to prevent excess
glare to oncoming vehicles.
The AFS control module software can detect an internal failure of the control module control circuits. The control module
will power the projector modules to the zero position and prevent further operation.
11
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Control module cover
12
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Static bending lamp bulb (All except NAS)
13
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Side lamp bulb
14
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Turn signal lamp bulb
