Part 1
Exterior Lighting
NOTE:
A = Hardwired; D = High speed CAN (controller area network) bus; O = LIN (local interconnect network) bus
CJB (central junction box)
The CJB (central junction box) receives exterior lighting related inputs from the following switches:
- LH (left-hand) steering column multifunction switch
- Side lamp position
- Headlamp position
- Automatic (AUTO) position (if fitted)
- Front fog lamp switch (if fitted)
- Rear fog lamp switch
- Turn signal indicators and high beam/headlamp flash
- Brake switch
- Headlamp leveling control (if fitted)
- Dimmer control
- Hazard flasher switch
- Rain/light sensor (LIN (local interconnect network) signal).
Circuit Protection
Two 60 Amp fusible links in the BJB (battery junction box) protect the power feed to the CJB (central junction box), LH (left-hand) and RH (right-hand) lighting circuits respectively. All exterior lighting circuits are protected by Field Effect Transistors (FETs), located in the CJB (central junction box), 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 (central junction box) 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 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 is in the off (power mode 0) or auxiliary (power mode 4) mode and the LH (left-hand) steering column multifunction 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 (central junction box) on the high speed CAN (controller area network) bus.
Crash Signal Activation
When a crash signal is transmitted from the RCM (restraints control module), the CJB (central junction box) 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 4, or the off power mode 0 or the RCM (restraints control module) no longer transmits the crash signal.For additional information, refer to Safety Belt System Locations
Headlamp Timer
The CJB (central junction box) 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 timer is set within the cluster menu - can set various times between 0 (off) and 120 secs.
The default timing is set to 30s but can be changed to 0s (OFF), 30s (default), 60s, 120s and 240s.For additional information, refer to Information and Message Center Locations
LEFT HAND STEERING COLUMN MULTIFUNCTION SWITCH
Left Hand Steering Column Multifunction Switch
The LH (left-hand) steering column multifunction switch allows the following selections:
- All exterior lamps off
- Side lamps on
- Headlamps on
- Automatic headlamps active
- Headlamp low/high beam
- Headlamp high beam flash
- Left/right turn signal indicator lamps
- Front/rear fog lamps
- Trip computer functions.
Headlamp Leveling
NOTE:
Headlamp leveling is not available on NAS vehicles with halogen headlamps.
A rotary thumbwheel controller is located on the outboard side of dashboard. The rotary thumbwheel controller 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
The dimmer rotary thumbwheel controller is located on the LH (left-hand) side of headlamp leveling rotary thumbwheel controller. The dimmer control provides a PWM (pulse width modulation) output to control the illumination brightness of the instrument panel and other instrument panel illumination.
The dimmer rotary thumbwheel switch 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 (pulse width modulation) output of between 8 and 12V to determine the brightness of the illumination.
Fog Lamps
The fog lamp switches are momentary switches, which when turned on or off, generate a LIN (local interconnect network) bus message from the LH (left-hand) steering column multifunction switch to the CJB (central junction box). The fog lamps remain active until deselected using the applicable fog lamp switch or the headlamps are switched off, or when power mode < 4.
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.
The automatic headlamp system uses a light sensor and the CJB (central junction box), which are connected via the LIN (local interconnect network) 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 Locations
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 (central junction box) on the LIN (local interconnect network) 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 LH (left-hand) steering column multifunction switch to be in the 'AUTO' position and a lights on request signal from the light sensor.
High beam on and flash functions
The high beam on and flash functions of the LH (left-hand) steering column multifunction switch 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 LIN (local interconnect network) bus to the CJB (central junction box) which activates the selected function.
Turn signal indicator lamps
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 (central junction box) 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. One sealed access cover 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.
Each headlamp has one access cover 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.
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.
Headlamps
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 D3 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 - Xenon
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.
The xenon headlamp system is controlled by the CJB (central junction box) 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 vice 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.
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 3.1A 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 (central junction box), the two xenon control modules and the two igniters. The xenon control modules (one per headlamp) receive an operating voltage from the CJB (central junction box) 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.