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 halogen headlamps have large complex surface reflectors to optimise the beam patterns in low beam only.A high beam only reflector is located on the inboard side of the headlamp. Headlamp leveling on the halogen headlamps is manually adjusted using a rotary thumbwheel located in the light switch module which operates leveling motors located in the headlamp.
The bi-function HID headlamps and the AFS headlamps use a projector unit with a D1S xenon bulb which operates in both low and high beam. An additional halogen high beam only reflector is located on the inboard side of the headlamp. 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.
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
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).
^ 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.
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 4 or the off power mode 0 or the RCM no longer transmits the crash signal.
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.
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.
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 ROW halogen headlamp has 2 H7 55W halogen bulbs for both high and low beam for ROW vehicles.On NAS vehicles, the low beam halogen headlamp uses an H11 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.