Part 1

Exterior Lighting

Exterior Lighting Component Location









GENERAL
The exterior lighting system comprises the following exterior lamps:
- Front and rear side lamps
- License plate lamps
- Side marker lamps (if fitted)
- Front and rear turn signal indicator lamps
- Side turn signal indicator lamps
- Stoplamps and high mounted stop lamp
- Reversing lamps
- Rear fog lamps
- Front fog lamps (if fitted)
- Cornering/Static bending lamps (if fitted) - All except NAS
- Low and high beam headlamps.

Exterior Bulb Type/Rating and LED Table
The following table shows the bulbs/LED's used for the exterior lighting system and their type and specification (where applicable).





The bulbs and the Light Emitting Diode (LED)'s are driven by Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) within the Central Electronics Module (CEM) which is an integral component of the Central Junction Box (CJB). An exception to this is the front and rear position lamps, front fog lamps and the reversing lamps which are supplied with power via relays within the CJB and are protected by conventional fuses.

CENTRAL JUNCTION BOX
The CJB is located behind the glove compartment and is connected to the vehicle wiring harness with 8 multiplugs.
The CJB receives four permanent battery power supplies via the Engine Junction Box (EJB).
The lighting circuits are not all protected by conventional fuses as some are protected by MOSFET's. The control circuitry within the CJB for each individual circuit can detect and isolate a problem circuit.
Failure of a lamp is not notified to the driver. If a turn signal indicator fails the turn signal warning indicator in the instrument cluster will flash at double speed.

Input Signals for Lamp Control
The CJB receives inputs from the following switches:
- Lighting control switch for side lamps, headlamps and auto headlamps (if fitted)
- Momentary push switches for front and rear fog lamps
- Left hand steering column multifunction switch for turn signal indicators and high beam/headlamp flash and Auto High Beam system
- Brake pedal switch
- Momentary push switch for hazard warning.
The switches are supplied with a 10mA supply from the CJB and switch to ground when operated. The CJB detects that a switch has been operated (ON) when its closing resistance is less than 100 Ohm and is detected as OFF when its resistance is more than 10K Ohm.
The lighting control switch uses a binary system which is detected by the CJB which determines the selected position. The output from the lighting control switch is shown in the following table:





The CJB also receives ignition status via hard wired connections from the stop/start switch.
A reverse gear engaged signal is also received on the high speed Controller Area Network (CAN) bus from the Transmission Control Module (TCM) to enable the CJB to activate the reverse lamps.
The CJB can receive a hazard warning indicator activation message from the Restraints Control Module (RCM), via the high speed CAN bus, in the event of a crash. The CJB can also activate the hazard warning indicators to signify vehicle locking to the driver.
On vehicles with Auto High Beam, the auto high beam control module outputs signals on the medium speed CAN bus to the CJB to control the high beam headlamps. Power for the auto high beam control module is supplied via a relay located in the EJB.

Circuit Protection
Operation of the lamps is performed using overload proof Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). The MOSFETs can detect overload, load interruption with the lamps switched on and short circuit to positive with the lamps switched off.
The MOSFETs are protected against short circuits, removing the requirement for the lamps circuits to be protected by fuses. The MOSFETs respond to heat generated by increased current flow caused by a short circuit. Normally this would cause the fuse to blow. The MOSFETs react to the heat increase and cut the supply to the affected circuit. Once the fault has been rectified or the MOSFET has cooled, the MOSFET will automatically reset and operate the circuit normally.
If an overload occurs, the current flow is dependant on the temperature of the related MOSFET and can be up to 20 times the rated current of the lamp. The MOSFET heats up and deactivates the load applied to the circuit. When the MOSFET cools the circuit is once again reactivated. This thermal cycling occurs continuously in the event of an overload occurring.
A number of lamps are controlled by relays and these circuits are protected by conventional fuses.

Bulb Monitoring
Bulb failure monitoring is performed by the CJB processor. The lamps are cold and warm monitored by the MOSFETs in order to detect bulb failure.

NOTE:
Relay controlled lamps have no diagnostic monitoring.
The CJB processor provides outputs to each MOSFET. The output switches the MOSFET to supply the required output to power the applicable lighting circuit. The microprocessor evaluates the circuits by detecting the returned signals from the controlling MOSFET.
When the bulb or LED is functioning normally, the output signal voltage from the controlling MOSFET is 0V. If a bulb or LED in the circuit fails, an open circuit occurs and the MOSFET outputs a signal of 5V to the processor. The signal is interpreted as a bulb or LED failure and generates a Diagnostic Trouble Code (DTC) which can be retrieved using an approved Land Rover diagnostic system.
Warm monitoring is performed continuously when the lights are switched on by evaluating the diagnostic output of the MOSFET switches. Cold monitoring is performed at 32 second intervals when the lights are switched off. The MOSFETs briefly switch on the lights for approximately 1 millisecond (this is insufficient to illuminate the bulb or LED) and checks the bulb or LED as per warm monitoring.
Cold monitoring is not possible for the low/high beam headlamps of vehicles using xenon bulbs. On these vehicles the cold monitoring of the low/high beam headlamps is switched off in the CJB. The CJB detects a failed xenon bulb via a reduction in current flow to the affected headlamp's xenon control module.
When a xenon bulb fails, the control module's current consumption falls to 60mA, which the CJB detects as unsuccessful bulb illumination.

Alarm Indications
The CJB can also display alarm visual indications for alarm arm, disarm and triggered conditions.
If the hazard warning lamps are active when a lock or unlock request is made, the hazard warning cycle is interrupted to allow the visual indication of the requested lock cycle. When visual indication is completed, the hazard warning operation will continue.
If the vehicle is involved in crash of a severity for the RCM to initiate deployment of the airbags, the control module outputs a hazard warning lamps on request on the medium speed CAN bus to the CJB. The hazard warning lamps will be activated and will continue until the RCM outputs a message to deactivate the hazard warning lamps.

Redundant Data Storage
The CJB stores data relating to the Vehicle Identification Number (VIN), total mileage and service interval indicator. This data is received by the CJB from the instrument cluster and used as a back-up in the event of instrument cluster replacement.
If the CJB is to be replaced, an approved Land Rover diagnostic system must be connected to the vehicle and the CJB replacement procedure followed to ensure that the stored data is transferred to the new unit.

Low Voltage Operation
If the battery voltage falls below 11.2V, the CJB operates the minimum lighting to preserve the remaining battery charge.

Crash Signal Activation
In the event of an accident of a severity to activate and deploy the airbags, the RCM requests various electrical operations to assist with the crash situation. The RCM requests via the bus systems to the CJB to activate the hazard warning lamps.

Security System Activation
In the event of the security system being triggered, the CJB requests activation of the hazard warning lamps.

Instrument Panel and Switch Illumination Dimming
The CJB controls the instrument cluster backlighting illumination and also illumination of all instrument panel switches.
The CJB supplies a power output to all switch illumination bulbs at a voltage determined by the position of the manual dimmer rheostat. The switch illumination is activated when the lighting control switch is in the side lamp or headlamp position.

LIGHTING CONTROL SWITCH
The lighting control switch is located in the driver's side of the instrument panel, below the outer fresh air vent. The switch contains a rotary switch for selecting the vehicle exterior lighting functions, a rheostat for instrument illumination dimmer, a front fog lamp switch and a rear fog lamp switch.









The rotary side and headlamp control switch has 2 connections to the CJB. These 2 connections supply a hardwired binary code to the CJB which correspond to the switch position selection made.
The front and rear fog lamp switches operate by completing earth paths for a reference voltage from the CJB when the switch is pressed. The fog lamp switches are momentary, non-latching switches which briefly complete an earth path which is sensed by the CJB.

Lighting Control Switch Illumination
The switch legends on the lighting control switch are illuminated at the same brightness as the instrument panel switches when the lighting control switch is moved from the 'O' (off) position to the side, headlamp or AUTO position.

Manual Headlamp Leveling Control (if fitted)
The manual headlamp leveling control is only available on vehicles with coil spring suspension and is used to lower the headlamps when an excessive load is placed on the rear of the vehicle, altering the vehicle attitude and raising the headlamp beam.
The control uses a rotary thumbwheel which is connected to a rheostat which gives a variable output to the leveling Direct Current (DC) motors. The motors respond to the output and move to adjust the headlamp position as required.
The control has three marked positions; 0 to 3. The rotary wheel moves in 6, half positions to give fine adjustment control over the headlamp position. The positions relate to vehicle loading or driving conditions as follows: Position 0 is the normal position for unladen driving. Positions 1 to 3 lower the headlamp beam to compensate for a drop in height of the rear of the vehicle.
- 0 = Driver only or driver and front seat passenger
- 0.5 = Driver, front seat passenger
- 1 = All seats occupied
- 1.5 = All seats occupied and maximum rear axle loading
- 2 = Driver only and maximum rear axle loading
- 3 = Can be used under certain driving conditions, i.e. off-road

Dimmer Control
The CJB provides a Pulse Width Modulation (PWM) output to control the illumination brightness of the instrument panel and other fascia illumination. The dimmer switch operates using a rotary thumbwheel which is connected to a rheostat.
The rheostat is a variable resistor which provides a high or low resistance according to its set position. The CJB provides an output to the rheostat measure the voltage passing through to ground. The CJB measures this voltage and uses it to calculate a PWM output of between 8 and 12V to determine the brightness of the illumination.

Automatic Headlamps
Refer to Automatic Headlamps.

HEADLAMP ASSEMBLY









Three types of headlamp are available; Halogen, Xenon or Xenon with Adaptive Front lighting System (AFS). The headlamps share a common, clear lens.
The headlamps are located behind the front carrier assembly. Each headlamp is secured to the front carrier assembly with two locking plates. The locking plate slides in grooves in the rear of the headlamp and two holes in each plate locate on pins on the carrier. Each locking plate is pressed down to lock the pins in the locking plate holes. The locking plates allow removal of the headlamp from the carrier for bulb changing without the requirement for special tools.
The rear of the headlamp unit has removable access panels which allow access to the bulbs for replacement. A large rubber cover allows access to the low/high beam bulb on both halogen and xenon headlamps. Another removable rubber cover provides access to the high beam only halogen bulb which is retained by a push fit. A smaller cover can also be rotated anti-clockwise to provide access to the turn signal indicator lamp bulb. The indicator bulb is a PH24WY orange bulb and is clipped into the cover and is pulled to remove. Below this cover is a removable cover which provides access to the side lamp bulb on halogen headlamps or the cornering lamp/static bending lamp bulb on xenon headlamps and the side marker lamp bulb on NAS models. On xenon headlamps the side lamps are LED's and therefore are not serviceable components.
The headlamps have two adjustment screws on the rear which allow for the manual setting of the vertical and horizontal alignment. 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 Service Repair Procedures manual for headlamp alignment data.
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 Reference Library (ERL) for pin details.
The low beam headlamps are switched on when the ignition is in ignition mode 6 and:
- the lighting control switch is in the headlamp position
- the lighting control switch is in the AUTO position and a 'lights on' signal is received by the CJB 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 is in ignition mode 6 and:
- the low beam headlamps are selected on in the headlamp position or activated via the AUTO feature
- The left hand steering column multifunction switch is pushed forward away from the driver
- The auto high beam system (if fitted) has switched on the high beam headlamps.
The high beam headlamps will be switched off when:
- The left hand steering column multifunction switch is moved rearward towards the driver
- The low beam headlamps are switched off
- The ignition mode is changed to the accessory mode 4 or ignition off
- The auto high beam system (if fitted) has switched off the high beam headlamps.