Part 2

Exterior Lighting

HEADLAMP ASSEMBLY

General
Three types of headlamp are available; Halogen, Bi-xenon or Adaptive Front lighting System (AFS). All headlamps share a common, clear lens.

The headlamps are located on the bonnet locking platform. Each headlamp is secured at the top to the bonnet locking platform with two screws and at the bottom to the front bumper support bracket with one screw. Headlamp removal is facilitated by removal of the radiator grille and removal of the three headlamp attachment screws.

Headlamp removal is required for replacement of any of the bulbs. The rear of the headlamp unit has removable access covers which allow access to the bulbs.

A large cover, which is rotated counter-clockwise to remove, allows access to the low/high beam bulb on both halogen and xenon headlamps.

A second cover, on the inboard side of the headlamp, can be removed to allow access to the high beam 'fill-in' lamp halogen bulb. The bulb is mounted in a holder with an extended end to aid removal.

A third cover, located on the outboard side of the headlamp, can be removed to give access to the side marker lamp bulb (NAS only), the side lamp bulb and the cornering/static bending lamp bulb (if fitted).

The turn signal indicator bulb is located on the outboard side of the headlamp. The bulb is a push fit into a holder which is secured in the headlamp body by rotating clockwise.

In all markets except NAS, the headlamps have two adjustment screws which allow for the manual setting of the vertical and horizontal beam alignment. A 6mm Allen key is used to rotate the adjusters to achieve the required setting. The inboard adjuster controls the vertical aiming and the outboard adjuster controls the horizontal aiming.

On NAS vehicles the headlamp is regarded as 'Visual Optically Left' (VOL) aiming. The adjustment screws have to be turned equal amounts to maintain the correlation in the vertical axis only. There is no horizontal adjustment. Refer to the headlamp alignment data and procedures.

Each headlamp has an integral sixteen pin connector which provides inputs and outputs for the various functions of the headlamp assembly. The usage of the pins differs between model variants. Refer to the Electrical Library and circuit diagrams for pin details.

Three breathers are located on the rear of the headlamp housing. The two lower breathers are fitted with 'C' shaped tubes and the upper breather has a 'T' shaped tube. The breather tubes which allow air flow in and out of the headlamp but prevent the ingress of moisture from rain, road spray or washing. If condensation occurs within the headlamp, check that the breather tubes are not blocked with mud etc before further action is taken.

Headlamp Operation
The lamps contained within the headlamp assembly have differing functionality depending on the function selected.

The low beam headlamps are switched on when the ignition switch is in the ignition position (II) and:
- the lighting control switch is the headlamp position
- the lighting control switch is in the 'AUTO' position and a 'lights on' signal is received by the LCM from the rain/light sensor.

The low beam headlamps can also be operated by the headlamp delay feature.

The high beam headlamps are switched on when the ignition switch is in the ignition position (II) and:
- the low beam headlamps are selected on in the headlamp position or the headlamps are activated by the AUTO feature and the left hand steering column multifunction switch is pushed forward, away from the driver
- the headlamp flash function is operated by pulling the left hand steering column multifunction switch towards the driver.

Common Headlamp Features

Turn Signal Indicators

The turn signal indicator bulb is located in a holder at the rear of the headlamp assembly, above the outer removable cover. The holder secures the bulb and has contacts which connect with mating contacts integral with the headlamp housing. Rotating the holder in a counter-clockwise direction allows the holder and the bulb to be removed.

Two types of bulb are used for the turn signal indicator. In all markets except NAS, the bulb is a 21W with orange colored glass and a bayonet fitting. On NAS vehicles the bulb is a 27W with orange colored glass and a wedge fitting.

Side Lamps
The side lamp bulb is accessible by removing the outer cover from the rear of the headlamp. The 5W wedge side lamp bulb is located in a holder which is a push fit into the rear of the reflector of the side lamp and static bending lamp (if fitted).

Side Marker Lamps (NAS only)
The side marker lamp bulb is accessible by removing the outer cover from the rear of the headlamp. The 5W wedge side marker lamp bulb is located in a holder which is a push fit into a molded receptacle in the outer edge of the headlamp. The side marker lamp illuminates a small rectangular section between the orange side reflectors on the outside of the headlamp.

Tourist Lever
On all headlamp variants a tourist lever mechanism is located on the side of the projector module. This mechanism moves a flap to blank off a portion of the beam spread to enable the vehicle to be driven in opposite drive hand markets without applying blanking decals to the headlamp lens.

The position of the tourist lever varies between headlamp variants and drive hand markets. The following lists detail the lever location and positions for home and opposite drive hand markets.

Halogen Headlamps
- UK LH side headlamp: tourist lever on the grille side
- UK RH side headlamp: tourist lever on the grille side
- ROW LH side headlamp: tourist lever on the grille side
- ROW RH side headlamp: tourist lever on the grille side

For RH side lamps, the tourist function is operated by pushing up the lever. The delivery condition is with the tourist lever pushed down. For LH side lamps, the tourist function is operated by pushing the lever down. The delivery condition is with the tourist lever pushed up

Bi-Xenon / AFS Headlamps
- UK LH side headlamp: tourist lever on the fender side
- UK RH side headlamp: tourist lever on the grille side
- ROW LH side headlamp: tourist lever on the grille side
- ROW RH side headlamp: tourist lever on the fender side

For all xenon and AFS headlamp variants the tourist function is operated by pushing the lever down. The delivery condition is with the tourist lever pushed up.

Static Headlamp Leveling - Halogen and Xenon Headlamps (not AFS)
Static vehicle headlamp leveling 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 leveling system is fully automatic, therefore the lighting control switch does not have a manual leveling rotary control.

Halogen Headlamps







The mono-halogen low beam only headlamp uses an H7 Long Life (LL) 55W halogen bulb. The lamp uses a projector lens, similar to the xenon headlamp. The projector module comprises an ellipsoidal lens and a reflector. The projector reflector collects the light produced by the halogen bulb and projects the light into a focal plane containing a shield. The contour of the shield is projected onto the road by the lens. The bulb is retained with conventional wire retaining clips.

A complex surface reflector is used for the halogen high beam 'fill-in' lamp. This type of reflector is divided into separate parabolic segments, with each segment having a different focal length. The high beam 'fill-in' lamp uses a H7LL 55W halogen bulb. The bulb is retained in an extended holder which allows easy access to the bulb. Once removed, the bulb can be removed from the holder by pulling it from its locating pegs.

Xenon Headlamps







Safety Precautions

WARNING: The Xenon system generates up to 28000 volts and contact with this voltage could lead to fatality. Make sure that the headlamps are switched off before working on the system.

The following safety precautions must be followed when working on the xenon headlamp system:
- DO NOT attempt any procedures on the xenon headlamps when the lights are switched on
- Handling of the D1S xenon bulb must be performed using suitable protective equipment, e.g. gloves and goggles. The glass part of the bulb must not be touched
- Xenon bulbs must be disposed of as hazardous waste
- Only operate the lamp in a mounted condition in the reflector.

The xenon headlamps use a complex surface reflector for the halogen high beam 'fill-in' lamp. This type of lamp has the reflector divided into separate parabolic segments, with each segment having a different focal length. A halogen H7LL 55W bulb is retained in an extended holder. The holder is secured in the rear of the high beam 'fill-in' lamp lens by rotating clockwise.

The xenon headlamp is known as 'bi-xenon' because it operates as both a low and high beam unit. The xenon bulb is located in a projector module which comprises an ellipsoidal lens with a solenoid controlled shutter to change the beam output from low to high.

NOTE: If the lighting control switch is in the 0 (off) position, the xenon lamps do not operate when the high beam 'flash' function is operated. If the lighting switch is in the headlamp position or the 'AUTO' position with the low beam headlamp active, the xenon low beam will remain on when the high beam 'flash' function is operated.

The xenon headlamp system is controlled by the LCM using a xenon control module and an igniter for each headlamp. The xenon control modules and the igniters provide the regulated power supply required to illuminate the xenon bulbs through their start-up phases of operation.

The xenon bulb is located in the rear of the projector module. The D1S xenon bulb incorporates an integral igniter unit and both components must be replaced if the bulb fails. A plastic mounting ring is fitted to the bulb and secures the bulb in the rear of the projector module. The mounting ring must be removed from the bulb and fitted to the replacement bulb.

The mounting ring locates in mating cut-outs in the xenon bulb. Refer to the illustration that follows for correct removal and replacement of the mounting ring.

Xenon Bulb Mounting Ring Replacement







Xenon/Halogen Headlamp Beam Comparison







The xenon low/high beam headlamps use ellipsoidal technology for the lens and reflector providing improved night time visibility compared to conventional halogen headlamps. The xenon headlamps provide the following benefits when compared to halogen headlamps:
- Longer bulb life - Approximately 3 to 5 times longer than a halogen bulb
- Increased light output - xenon headlamps output 3 to 4 times more light on the road surface than halogen headlamps
- Blue/White light which is closer to natural daylight - compared to a yellow light produced by a halogen bulb
- Improved night time driving visibility - xenon lamps produce a wider and brighter beam in front of the vehicle than conventional halogen bulbs
- Lower running temperatures
- Lower power consumption.

The xenon headlamp is a self contained unit located within the headlamp assembly. The unit comprises a reflector, an adaptor ring, the lens, a shutter controller and the xenon bulb, which as an assembly is known as the projector module.

The reflector is curved and provides the mounting for the xenon bulb. The bulb locates in a keyway to ensure correct alignment in the reflector and is secured by a plastic mounting ring. The bulb is an integral part of the igniter and is electrically connected by a connector located in the igniter unit.

The shutter controller is a solenoid which operates the shutter mechanism via a lever. The shutter is used to change the beam projection from low beam to high beam and visa versa.

The xenon bulbs illuminate when an arc of electrical current is established between two electrodes within the bulb. The xenon gas sealed in the bulb reacts to the electrical excitation and the heat generated by the current flow to produce the characteristic blue/white light.

To operate at full efficiency, the xenon bulb goes through three stages of operation before full output for continuous operation is achieved. The three phases are; start-up phase, warm-up phase and continuous phase.

In the start-up phase, the bulb requires an initial high voltage starting pulse of up to 30000 volts to establish the arc. This is produced by the igniter. The warm-up phase begins once the arc is established. The xenon control module regulates the supply to the bulb to 2.6A which gives a lamp output of 75W. During this phase, the xenon gas begins to illuminate brightly and the environment within the bulb stabilizes ensuring a continual current flow between the electrodes. When the warm-up phase is complete, the xenon control module changes to continuous phase. The supply voltage to the bulb is reduced and the operating power required for continual operation is reduced to 35W. The process from start-up to continuous phase is completed in a very short time.

The xenon system is controlled by the LCM, the two xenon control modules and the two igniters. The xenon control modules (one per headlamp) receive an operating voltage from the LCM when the headlamps are switched on. The modules regulate the power supply required through the phases of start-up.

The igniters (one per headlamp) generate the initial high voltage required to establish the arc. The igniters have integral coils which generate high voltage pulses required for start-up. Once the xenon bulbs are operating, the igniters provide a closed circuit for regulated power supply from the control modules.

Adaptive Front Lighting System (AFS) Headlamps
The AFS headlamp is similar in its construction to the xenon headlamp described previously. The projector module is constructed and operates as described for the xenon headlamp with the addition of the AFS system which allows the projector module to be moved vertically and horizontally. The following description covers the additional differences to the xenon headlamp with AFS.







The AFS is a system to improve driver visibility under differing driving conditions. AFS provides a larger visible area which is illuminated when cornering by adjusting the position of the beam distribution on the road. Horizontal adjustment is made automatically to the most suitable orientation for the driving conditions using steering angle and information from other vehicle sensors.

AFS is only available with xenon headlamps and also includes the dynamic headlamp leveling system described in the 'Headlamp Leveling' section of this document. The bi-xenon module within the headlamp is controlled by actuator motors which rotate the projector module on its vertical and horizontal axes to adjust the beam output to suit the cornering conditions and vehicle inclination. Only the bi-xenon lamp projector module swivels, the halogen high beam lamp unit remains static.

The AFS is controlled by an AFS control module which is located at the bottom of the left hand 'A' pillar. The module is connected to and controls an AFS power module located on the base of each headlamp. Signals from the AFS control module are processed by the AFS power module which powers stepper motors to adjust the vertical and horizontal alignment of the projector module. The AFS power module also controls and regulates the operation of the static bending lamp (if fitted) which is requested by the AFS control module but controlled by the LCM.

AFS Concept







The AFS xenon headlamp construction is similar to the non-AFS xenon headlamp assembly. The AFS headlamp has a xenon control module located on the underside of the lamp assembly. An additional AFS power module is located in front of the xenon control module. The AFS power modules supply the correct voltage to stepper motors which control the positioning and movement of the AFS projector module.

The AFS assembly contains an additional carrier frame which provides the location for the AFS actuators. The remaining lamps are as described previously. The AFS headlamp also incorporates a static bending lamp.

The carrier frame is attached to the AFS vertical actuator. The projector module has a central pivot point which allows the module to move horizontally in response to operation of the AFS horizontal actuator.

The AFS actuators are bi-polar (2 phase) dc stepper motors which are driven by a power output from the AFS power module. Each stepper motor receives its position information from the AFS control module via the applicable AFS power module. When the actuators are powered to their requested positions, a holding current is applied to maintain the actuator position.

The actuators do not supply a positional feedback signal to the AFS control module. Each stepper motor requires referencing each time the AFS system becomes active. When the AFS system is active, each vertical actuator is driven in the low beam position and each horizontal actuator is driven to an inboard position until a mechanical stop in the actuator is reached. Once the stop is reached a step counter in the AFS control module is set to zero and the actuator is then powered to the operating position as determined by the AFS control module software.

The AFS control module receives front and rear suspension height data to provide dynamic headlamp leveling 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.

AFS Control Module
The AFS control module is located at the bottom of the left hand 'A' pillar, behind the trim panel.

The AFS control module is a dual functionality unit which also incorporates software to control the dynamic headlamp leveling. The AFS control module is connected to the high speed CAN bus and receives inputs from other vehicle systems on the status of the following parameters:
- Steering angle
- Vehicle speed
- Headlamp status
- Engine running
- Reverse gear selected
- Automatic lighting on.

The AFS will only operate when the AFS control module receives an engine running signal on the CAN bus. When the engine running signal is received the AFS control module performs an initialization routine.

The AFS will also function when the lighting control switch is in the AUTO position and the AFS control module receives a lights on signal from the rain/light sensor and an engine running signal.

The AFS control module then monitors the inputs from the other vehicle systems to control the AFS functionality according to cornering angles and vehicle speed.

The AFS control module is connected to each AFS power module on a private LIN bus. The power modules read operating values supplied from the AFS control module and control the output drivers for the stepper motor actuators inside the headlamp assembly.