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Electrical system 17
9-5
Brief description
The headlight assembly contains a xenon lamp
with ignition transformer, control module, beam
length adjustment motor, halogen bulb and
parking light bulb.
The AHL (Automatic Headlight Levelling) control
module governs the current/voltage supply to
the xenon lamp. These lamps require very high
voltages (approx. 23000 volts) before they
ignite. The normal operating voltage is around
85V. The control module also governs the
stepping motors for the automatic beam length
adjustment. The AHL control module receives
information from the front and rear load angle
sensors concerning the front and rear height of
the car and then adjusts the angle of the
headlights based on this information.
Xenon lamps always light with the same
brightness. The light beam from a xenon lamp is
limited by a screen which is opened for main
beam use by a solenoid that is activated from
the control module. This increases the beam of
light from the lamp.
There is a halogen bulb mounted in the
headlight assembly housing. When the
headlight flashers are used while the low beam
is turned off, only the halogen bulb lights up
(sometimes called the “flash to pass” function).
In many world markets, the halogen bulb comes
on together with the xenon lamp for main beam
(high beam).
Due to U.S. Federal Regulations, the halogen
bulb does not come on simultaneously with the
xenon lamp for main beam (high beam) on the
U.S. specification vehicles.
Bi-Xenon Headlights (Available on Arc & Aero)