Part 1

Exterior Lighting

COMPONENT LOCATION









OVERVIEW
Three levels of exterior lighting are available depending on vehicle specification:
- Halogen headlamps
- Bi-xenon High Intensity Discharge (HID) headlamps
- Bi-xenon HID Adaptive Front lighting System (AFS) headlamps.
A light switch module is located in the instrument panel and allows the driver to select the appropriate operation of the exterior lighting systems.
The rear lamp assemblies contain side lamps, stop lamps, reverse lamps, turn signal indicators and rear fog lamps. On North American Specification (NAS) vehicles the rear lamp assembly also includes a side marker lamp. The rear lamp assemblies require removal for bulb replacement. Two reflectors are mounted in the rear bumper.
All versions of the headlamps have impact resistant polycarbonate lens'. Removable covers at the rear of the headlamps allow for bulb replacement. The headlamps require removal for bulb replacement.
The headlamps use a projector unit, bi-function HID headlamps and the AFS headlamps use a D1S xenon bulb which operates in both low and high beam. Halogen projector headlamps use a H11 halogen bulb which only operates in low beam. An additional halogen high beam only reflector is located on the inboard side of the lamp unit. Headlamp leveling is automatic on the HID headlamps. Front and rear height sensors are located on the Left Hand (LH) side of the front and rear axles. These measure the vehicle attitude and a headlamp leveling module, which is located on the bulkhead 'A' pillar behind the glovebox, automatically controls the headlamp vertical alignment. Manual headlamp leveling is uses only on ROW vehicle fitted with halogen projector lamps, a rotary leveling thumbwheel is located on the RH side of the light switch module.
Headlamp powerwash is a standard fitment on HID headlamps.
Turn signal indicators and high and low beam functions are controlled from the LH steering column multifunction switch. The turn signal indicators have a lane change feature. A single press and release of the multifunction switch in either direction will operate the selected turn signal indicators for 3 cycles.
The exterior lighting is controlled by the CJB. The CJB is the main controlling module for vehicle body systems and is located behind the glovebox in the instrument panel.
The CJB provides circuit protection for all exterior lighting circuits.

Exterior Bulb Type/Rating
The following table shows the bulbs used for the exterior lighting system and their type and specification.





CONTROL DIAGRAM

NOTE:
A = Hardwired; D = High speed CAN bus; O = LIN bus









CENTRAL JUNCTION BOX (CJB)
The CJB receives exterior lighting related inputs from the following switches:
- Light switch module
- Side lamp position
- Headlamp position
- Automatic (AUTO) position (if fitted)
- Front fog lamp switch (if fitted)
- Rear fog lamp switch
- Dimmer control
- Headlamp leveling control (if fitted).
- Brake switch
- LH steering column multifunction switch for turn signal indicators and high beam/headlamp flash
- Hazard flasher switch
- Rain/light sensor (LIN signal).

Circuit Protection
Two 60 Amp fusible links in the battery junction box protect the power feed to the CJB LH and RH lighting circuits respectively. All exterior lighting circuits are protected by Field Effect Transistors (FETs), located in the CJB, which can detect overloads and short circuits.
The FETs respond to heat generated by increased current flow caused by a short circuit. On a normal circuit this would cause the fuse to blow. The FETs respond to the heat increase and disconnect the supply to the affected circuit. When the fault is rectified or the FET has cooled, the FET will reset and operate the circuit normally. If the fault persists the FET will cycle, disconnecting and reconnecting the power supply. The CJB stores fault codes which can be retrieved using a Land Rover approved diagnostic system. The fault code will identify that there is a fault on a particular output which assist in fault detection.

Alarm Indications
The exterior lighting system is used for alarm arm and disarm requests. When the driver locks or unlocks the vehicle, a visual indication of a successful lock or unlock request is displayed to the driver by the hazard flashers operating a number of times. For additional information, refer to Anti-Theft - Active Anti-Theft - Active

Lights On Warning chime
When the ignition in the off (power mode 0) or auxiliary (power mode 4) mode and the lighting control rotary switch is in the side lamp or headlamp position, a warning chime will sound if the driver's door is opened. This indicates to the driver that the exterior lights have been left on. The chime is generated from the instrument cluster sounder on receipt of a lights on signal, a door open signal and an ignition switch off signal from the CJB on the high speed CAN bus.

Crash Signal Activation
When a crash signal is transmitted from the Restraints Control Module (RCM), the CJB activates the hazard flashers and the turn signal indicators in the instrument cluster. The hazard flashers will continue to operate until the ignition mode is changed to the auxiliary power mode 4or the off power mode 0 or the RCM no longer transmits the crash signal. For additional information, refer to Air Bag Systems Description and Operation

Headlamp Timer
The CJB controls a headlamp timer function which allows the headlamps to remain on for a period of time after leaving the vehicle. This is a driver convenience feature which illuminates the driveway after leaving the vehicle.
This feature can only be activated by pulling the high beam ' flash-to-pass' on the LH steering column multifunction switch. It can be deactivated either by timing out or by pulling the multifunction switch again.
The default setting can be changed by a Land Rover or authorized dealer. The default timing is set to 30s but can be changed to 0s (OFF), 30s (default), 60s, 90s, 120s, 150s and 180s.For additional information, refer to Information and Message Center Description and Operation

LIGHT SWITCH MODULE









The light switch module is located in the driver's side of the instrument panel and allows the driver to control the operation of the exterior lighting system. Three variants of the module are available to cover different vehicle specifications and market variants.
All switch operations are detected by the light switch module and sent as Local Interconnect Network (LIN) messages to the CJB.

Lighting Control Rotary Switch
The light control module has a central rotary switch which allows the following selections:
- All exterior lamps off
- Side lamps on
- Headlamps on
- Automatic headlamps active.

Headlamp Leveling (ROW halogen headlamps only)

NOTE:
Headlamp levelling is not available on NAS vehicles with halogen headlamps.
A rotary leveling thumbwheel is located on the RH side of the light switch module. The rotary thumbwheel is connected to a rheostat which gives a variable output to the headlamp leveling stepper motors. The motors respond to the output and move to adjust the headlamp vertical alignment as required.
The control has no defined positions but can be adjusted as required to compensate for a drop in height at the rear of the vehicle and avoid dazzle to oncoming drivers.

Dimmer Control
A rotary dimmer thumbwheel is located on the LH side of the light switch module. The dimmer control provides a Pulse Width Modulated (PWM) output to control the illumination brightness of the instrument panel and other instrument panel illumination.
The dimmer switch operates using a rotary thumbwheel which is connected to a rheostat and a high side switch. The rheostat is a variable resistor which provides a high or low resistance according to its set position. This output is passed to a switchable capacitor or a high side switch. The high side switch uses the output from the rheostat to determine the switching frequency of the capacitor which provides the PWM output of between 8 and 12V to determine the brightness of the illumination.


Fog Lamps
Two switches are provided for selection of the front and rear fog lamps. The front fog lamp switch is only fitted to vehicles with front fog lamps.
The fog lamp switches are momentary switches, which when pressed, generate a LIN bus message from the light switch module to the CJB. The fog lamps remain active until deselected using the applicable fog lamp switch or the headlamps are switched off or the ignition power mode 6 is changed to the off power mode 0.

Automatic Headlamps
The automatic headlamp function is a driver assistance system. The driver can override the system operation by selection of side lamp or headlamp on if the ambient light conditions require front and rear lighting to be active.
The automatic headlamp system uses a light sensor and the CJB, which are connected via the LIN bus to control the headlamp functionality.
A light sensor is incorporated in the rain/light sensor located on the inside of the windshield, below the rear view mirror. The wiper system also uses the rain/light sensor for automatic wiper operation. For additional information, refer to Wipers and Washers Description and Operation
The light sensor measures the ambient light around the vehicle in a vertical direction and also the angular light level from the front of the vehicle. The rain/light sensor uses vehicle speed signals, wiper switch position and the park position of the front wipers to control the system.
The automatic headlamp operation uses ambient light levels which are monitored by photodiodes incorporated in the rain/light sensor. The rain/light sensor sends a lights on/off request to the CJB on the LIN bus, which responds by switching on the low beam headlamps, front side lamps, license plate lamps and rear tail lamps. The automatic headlamps are activated under the following conditions:
- Twilight
- Darkness
- Rain
- Tunnels
- Underground or multistoried car parks.
Operation of the automatic headlamps requires the ignition to be on (power mode 6), the lighting control rotary switch to be in the 'AUTO' position and a lights on request signal from the light sensor.

LEFT HAND STEERING COLUMN MULTIFUNCTION SWITCH









The steering column multifunction switch is located on the left hand side of the steering column and controls the following functions:
- Headlamp low/high beam
- Headlamp high beam flash
- Left/right turn signal indicator lamps
- Trip computer functions.
The high beam on and flash functions are hardwired to the steering wheel module. When the switch is operated in either position a ground path via the switch is completed for the selected function which is sensed by the steering wheel module. The steering wheel module then issues a message on the Local Interconnect Network (LIN) bus to the CJB which activates the selected function.
The turn signal indicator lamps are connected and operate in a similar way with the ground path completed for the selected function which is sensed by the steering wheel module the module then issues a message relating to the selected function to CJB which in turn activates the requires turn signal indicator.

HEADLAMP ASSEMBLY
Three headlamp variants are available depending on model specification; halogen, bi-xenon and bi-xenon with Adaptive Front lighting System (AFS).
The headlamps are sealed units, with scratch resistant polycarbonate lenses bonded to the headlamp body. Two sealed access covers and a sealed housing provide a watertight environment for the headlamp internal components. To prevent fogging of the lens and to allow the headlamp unit to 'breath' in response to internal temperature changes, a vent is located at the outer rear face of the headlamp body. The vent is covered by a Gortex waterproof membrane. This allows ventilation of the headlamp while preventing the ingress of water.
The headlamps can be quickly removed for bulb replacement due to the unique 'Rail Lock' system. Headlamp access requires the removal of 2 bolts securing the headlamp to the bonnet closing panel. A locking lever at the rear of the headlamp can then be lifted, releasing a locking tab at the base of the headlamp body. The headlamp can then be pulled forward on the rail and, after disconnection of the harness connector, removed from the vehicle. The 'Rail Lock' system ensures that the headlamp alignment is not compromised during the removal process.
Each headlamp has two access covers at the rear. The larger cover requires the locking lever to be released from its guide slots to allow access to the cover. The cover can then be removed by releasing 2 tabs to allow the high and low beam bulbs to be changed. The circular rubber cover is a push fit onto the rear of the lamp assembly. Removal of the cover gives access to the side lamp and turn signal indicator bulbs.
On NAS vehicles, the side lamp is colored orange. The side lamp lens is designed so that light from the side lamp bulb also illuminates the orange colored reflector area at the side of the lamp without the need for an additional bulb.

Halogen Headlamps









The low beam halogen headlamps use an H11 55W halogen bulb, the high beam headlamps use an H7 55W halogen bulb.

Bi-Xenon Headlamps









The xenon headlamp uses a complex surface reflector for the halogen fill-in high beam only unit. This uses the same halogen H7 55W bulb as used on the halogen headlamp. A bi-xenon projector module is fitted for the low beam headlamp but also operates as a high beam unit.

Safety Precautions
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.

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.

Headlamp Construction and Functionality
The xenon lamp or High Intensity Discharge (HID) lamp as they are sometimes called, comprises an ellipsoidal lens with a solenoid controlled shutter to change the beam output from low to high beam.

NOTE:
If the light control module rotary switch is in the OFF position, the xenon lamps do not operate when the high beam 'flash' function is operated. If the rotary switch is in the headlamps position or AUTO position with the low beam lamps active, the xenon low beam will remain on when the high beam 'flash' function is operated.
The xenon headlamp system is controlled by the CJB using a control module for each headlamp and an igniter. The 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 headlamp is a self contained unit located within the headlamp assembly. The unit comprises a reflector, the lens, a shutter controller and the xenon bulb, which as an assembly is known as the projector module.
The reflector provides the mounting for the xenon bulb which is an integral part of the igniter. The igniter locates in an aperture at the rear of the reflector and is secured with 2 Torx screws to ensure correct alignment in the reflector.
A shutter is used to change the beam projection from low beam to high beam and visa versa. The shutter controller is a solenoid which operates the shutter mechanism via a lever. When the shutter is in the low beam position, it masks some of the light emitted from the reflector, providing a defined low beam cut-off.
A tourist lever mechanism is located on the right hand 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 beam is changed by removing the cover at the rear of the lamp assembly and moving a small lever located at the side of the projector module.
The xenon bulb illuminates 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 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 igniters. The warm-up phase begins once the arc is established. The xenon control modules regulate the supply to the bulbs 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 modules change 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 CJB, the two xenon control modules and the two igniters. The xenon control modules (one per headlamp) receive an operating voltage from the CJB 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.