Part 3
Exterior Lighting
AFS Operation
The AFS controls the swiveling angle of each projector module using speed and steering angle signals. The angles of each projector module differ to give the correct spread of light, e.g. when turning left, the left hand projector module will have a greater swiveling angle than the right hand projector module.
Initialization Procedure
When the AFS control module receives an ignition on signal, the control module performs the initialization procedure which ensures that the headlamps are correctly aligned on both their vertical and horizontal axes.
The headlamp leveling initialization takes less than 3 seconds to complete. The headlamp leveling motors are powered from their current position, which can be either the upper or lower limit or somewhere in between, to their lower position and then back to the 0 degrees position.
The AFS swivel initialization starts less than 1 second after the headlamp leveling initialization is activated to ensure that the headlamps are at or below the 0 degree position in the vertical axis, thus preventing glare to oncoming vehicles. The AFS swivel initialization is completed in less than 2.5 seconds. The LH and RH AFS actuator motors are powered from the 0 degree position to their fully inboard position, then to their fully outboard position and then back to the 0 degree position.
Failure Mode
In the event of a failure of the AFS system, a warning indicator in the instrument cluster is illuminated to warn the driver. The AFS warning indicator illuminates when the ignition switch is in position (II) and will flash continuously until the fault is rectified. The AFS warning indicator will also be illuminated if a failure of the steering angle sensor or the vehicle speed signal is detected.
Illumination of the AFS warning indicator does not necessarily mean that there is a fault with the AFS system. The fault may be caused by a failure of another system preventing the AFS system operating correctly.
The AFS control module performs a diagnostic routine every time AFS is requested. If any fault is found, the AFS control module will suspend the operation of the AFS function.
If the AFS leveling system has failed with the xenon projector module in a position other than the correct straight ahead position, the AFS control module will attempt to drive the projector module to a position a small amount lower than the standard position. If the swivel function has failed, the AFS control module will lower the projector module using the leveling actuator motors to a position much lower than standard to prevent excess glare to oncoming vehicles.
The AFS control module software can detect an internal failure of the control module control circuits. The control module will power the projector modules to the zero position and prevent further operation.
Faults can be investigated by interrogating the AFS control module using the Land Rover recommended diagnostic tool to check for fault codes.
Static Bending Lamps
NOTE: The static bending lamps are not fitted to NAS vehicles
The static bending lamps, which are a standard feature on AFS headlamps, are designed to illuminate the direction of travel when cornering at low speeds. The static bending lamp functionality, which controlled by the LCM, is unique to vehicles with AFS headlamps and operates using inputs from the steering angle sensor.
The static bending lamp is incorporated into the outer part of the headlamp assembly and shares the same housing and reflector as the side lamp. The design of the lens projects a spread of light from the vehicle at approximately 45 degrees to the vehicle axis.
The static bending lamp uses a 35W Halogen H8 bulb which locates in a holder which is connected via wires to the main connector on the headlamp housing. The holder is located in an aperture in the headlamp housing and rotated to lock. The bulb is accessible via a removable cover at the rear of the headlamp housing.
AFS Control
The static bending lamps operate with a steering angle sensor CAN signal which is received by the AFS control module and the LCM. The AFS control module sends a static bending lamp on request to the LCM which activates the static bending lamp bulb.
When the operation parameters of the lamp are reached, the LCM illuminates the static bending lamp bulb on using a full power PWM voltage. When the lamp is switched off, the LCM fades the bulb off by decreasing the PWM voltage in a linear manner depending on steering angle and vehicle speed.
Dynamic Headlamp Leveling - AFS Headlamps Only
Dynamic headlamp leveling is only available on vehicles with AFS headlamps.
The dynamic headlamp leveling adjusts the vertical alignment of the headlamps as a rapid response to changes in vehicle attitude due to acceleration or braking.
The dynamic system is fully automatic, therefore the lighting control switch does not have a manual leveling rotary control.
NOTE: The AFS system also operates in conjunction with the static vehicle leveling system as described previously.
The dynamic system comprises the following components:
- Two headlamp leveling motors
- AFS control module
- Engine running signal from engine control module
- Vehicle speed information from ABS module
- Vehicle height information from air suspension control module.
When the ignition switch is in position (II), power is supplied to the lighting control switch via the ignition relay in the Battery Junction Box (BJB) and to the AFS control module. When the lighting control switch is moved to the side lamp or headlamp position, the supply from the ignition relay is passed to the AFS control module.
NOTE: When the AFS control module receives an ignition on signal, the control module performs an initialization procedure for both the AFS and headlamp leveling motors.
The system operates by the AFS control module receiving inputs on the CAN from the air suspension control module for front and rear vehicle height, from the engine control module for engine running signal and from the ABS module for stop lamp switch active (brakes applied) and vehicle speed. The AFS control module processes these signals and provides an output to the headlamp leveling motors to adjust the headlamp vertical aim according to vehicle speed and attitude.
NOTE: In markets with Daytime Running Lamps (DRL), the dynamic headlamp leveling system will not operate when the DRL are active.
AUTOMATIC HEADLAMPS
The automatic headlamp function is a driver assistance system. The driver can override the system operation by selection of side lamps or headlamps on if the ambient light conditions require front and rear lighting to be active.
The automatic headlamp system uses a rain/light sensor and the LCM, which are connected via the K bus and I bus to control the headlamp functionality. The 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. Refer to the Wipers and Washers section for details of the rain/light sensor and 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 rain/light sensor can detect if the vehicle has entered a tunnel or similar environment and will activate the headlamps on entry to the tunnel when the ambient and forward light levels have fallen quickly. When the tunnel is exited, the rain/light sensor detects the sudden increase in light levels and requests the lights to be switched off.
Certain light and weather conditions are not detected accurately by the rain/light sensor. The driver should override the automatic headlamps function if in any doubt about weather conditions and the requirement for exterior lights to be active.
The automatic headlamp operation uses ambient light levels which are monitored by a photodiode incorporated in the rain/light sensor. The rain/light sensor sends a lights on/off request to the LCM on the K bus, which responds by switching on the low beam headlamps, front side lamps and rear tail lamps. The automatic headlamps are activated under the following conditions:
- Twilight
- Darkness
- Rain
- Snow
- Tunnels
- Underground or multi-level car parks.
Operation of the automatic headlamps requires the ignition switch to be in position II, the lighting control switch to be in the 'AUTO' position and a lights on request signal from the light sensor.
NOTE: The front fog lamps will not operate if the automatic control lamps are switched on.
If the automatic headlamp function has been selected and the ambient light falls below a pre-defined level then the front and rear fog lamps can be manually activated. If the ambient light rises above that level then the fog lamps will be deactivated along with the rest of the lamps. If the ambient light then falls below this level again the lamps will be activated, but the fog lamps which were previously selected will not.
HEADLAMP DELAY
The LCM controls a headlamp delay function which illuminates the driveway after leaving the vehicle. The headlamp delay will operate on low beam headlamps only regardless of the position of the left hand steering column multifunction switch.
The delay is operated when the ignition is switched off and the key removed with the headlamps switched on (not in the AUTO position). The message center displays a 'HEADLIGHTS ON' message accompanied by a chime from the sounder. When the lighting control switch is moved to the 'off' position, the message center displays a 'HEADLIGHT DELAY' message and the low beam headlamps are activated for a period of approximately 45 seconds. After the delay period, the LCM automatically switches off the delay function, extinguishing the headlamps.
If the lighting control switch is in the 'AUTO' position and the ignition is switched off and the key is removed, the headlamp delay will not operate. The left hand steering column multifunction switch must be operated in the headlamp 'flash' position to activate the headlamp delay. The headlamps will extinguish after the delay period has expired.
INSTRUMENT CLUSTER WARNING LAMP ILLUMINATION
The warning lamps in the instrument cluster for left and right turn signal indicator, front and rear fog lamps and headlamp low and high beam and side lamps are activated by the LCM via messages to the instrument cluster on the I Bus. The synchronization of the turn signal indicator warning indicator lamps with the external turn signal indicator lamp frequency is controlled by a cyclic transmission of the light status on the I Bus.
The AFS warning lamp is controlled by a signal from the AFS control module.
FRONT FOG LAMPS
The front fog lamps are located in the front bumper. Each lamp is secured to three lugs in the bumper and retained with self tapping screws and fasteners. Each lamp has two adjusting screws which provide for the vertical and horizontal alignment of the beam.
The 55W halogen bulb is located in a holder. The holders are secured in the lamp housing by rotating through approximately 10 degrees. The holder has a connector to allow for connection to the electrical harness.
TAIL LAMP ASSEMBLY
The rear tail and turn signal indicator lamp assemblies are located on the outer corner of each rear wing panel.
The lamp assembly is retained by two integral plastic clips which locate in corresponding clips secured to the body panel. The assembly is further retained by two self tapping screws which are accessed from inside the taildoor aperture. To remove the assembly, after removing the screws, the assembly must be prized at two indentations to release the clips. A non-metallic tool must be used with care to avoid damage to the paint finish.
The direction indicator, fog lamp and side lamp bulbs are located in a holder. The holder is secured in the lamp housing by two plastic clips. The holder has a connector to allow for connection to the electrical harness.
The upper lamp aperture is for the stop lamp and the turn signal indicator. The stop lamp comprises a plastic holder with contains 19 LED's. This illuminates through a circular prism lens in the center of the lamp to display the stop lamp in a red color. The turn signal indicator lamp is located behind the stop lamp LED unit. The bulb is located in a reflector unit which emits the turn signal indicator light around the outer diameter of the stop lamp LED assembly.
On 3.0 Td6 and 4.4L V8 models, the turn signal indicator uses a PY21W orange bulb. On 4.2L V8 supercharged models a PW21W Osram Diadem bulb is used. The Diadem bulb emits an orange light when illuminated but is not orange colored when inactive.
The lower lamp aperture is divided into two parts and provides for the tail lamp and the rear fog lamp.
The rear fog lamp uses different bulbs depending on model. On 4.4L V8 models the rear fog lamp uses a P21W bayonet fitting bulb. On 4.2L V8 supercharged models the rear fog lamp uses a PR21W. This is also used for the tail lamp, operated by a PWM output from the LCM to produce a lower wattage output than the fog lamp.
The upper half of the tail lamp aperture is used solely for the tail lamp and uses a P21W/5W bulb on 4.4L V8 models and a PR21/5W bulb on 4.2L V8 supercharged models. Only the 5W filament is used for the tail lamp, with the 21W filament not used by any function.
On NAS vehicles, an additional lamp holder is used to accommodate the side marker lamp. The lamp assembly lens has a vertical section which is used as the side marker illumination required for the NAS market. The side marker lamp bulb is a 5W bayonet fitting.
All bulbs in the tail lamp assembly are monitored by the LCM and, if a failure is detected, alerts the driver via the instrument cluster message center.
SIDE REPEATER LAMPS
The side repeater lamps are located in the front fenders, forward of the louvered air vents. The side repeater lamps are clipped into the fender aperture and can be removed by pushing forwards and pulling outwards from the fender.
The side repeater lamps use a capless 5W bulb which is pressed into contacts in a holder. The holder is located in the lamp assembly. These lamps are not monitored by the LCM and if a failure occurs the driver will not receive a message.
REVERSING LAMPS
The reversing lamps are located in the lower tail door and positioned at either side of the license plate. The lamps are secured in the tail door with a clip at the bottom and positively secured with a screw at the top.
Each reversing lamp uses a 6W bayonet type bulb. The LCM monitors the bulbs and, if a failure is detected, alerts the driver via the instrument cluster message center.
LICENSE PLATE LAMPS
Two license plate lamps are located in the trim above the license plate in the lower tail door. The lamps are press fitted in their apertures and secured by an integral plastic clip.
Each lamp uses a 5W festoon type bulb. The LCM monitors the bulbs and, if a failure is detected, alerts the driver via the instrument cluster message center.
HAZARD WARNING LAMPS
The hazard warning lamps use the front and rear turn signal indicator lamps as previously described. These are controlled by the LCM in response to a hazard warning lamp request from the instrument panel switch.
Crash Signal Activation
In the event of an accident of a severity to activate and deploy the airbags, the restraint control module requests various electrical operations to assist with the crash situation. The restraints control module requests via the bus systems to the LCM to activate the hazard warning lamps. These will continue to operate until deselected using the hazard warning lamp switch in the instrument panel. The lamps flash at a frequency which is the same as the frequency used to flash the headlamp high beam in the same situation.
DAYTIME RUNNING LAMPS (DRL)
DRL operation is detailed in a separate section.
LEFT HAND STEERING COLUMN MULTIFUNCTION SWITCH
The left hand 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 indicators
- Trip computer functions.
The high beam on and flash functions are connected on a single wire to the LCM. The switch assembly contains resistors and the ground for each selection is passed through a different resistor for each selection. The same also applies to the turn signal indicators. The LCM senses the resistance on the ground wire and determines which function has been selected.
The turn signal indicators incorporate a lane change function. To activate the lane change function old the lever partially up or down against spring pressure to indicate a lane change. The directional indicator will flash three times. The lane change function can be enabled or disabled by a Land Rover Dealer.
TRAILER MODULE
The trailer module is fitted to all vehicles and is located in the RH side of the luggage compartment, behind the removable trim panel, adjacent to the rear auxiliary fusebox. The module is required to separate the load circuits of the trailer from the load circuits of the towing vehicle. This allows separate monitoring of the vehicle lamps and the trailer circuits.
The trailer module comprises a double transistor for reversing lamp and rear fog lamp operation and overload proof MOSFET circuit breakers for the following lamps:
- Left turn signal indicator
- Right turn signal indicator
- Stop lamps
- Left tail lamp
- Right tail lamp
- Permanent trailer battery supply circuits.
The above lamps are connected to the trailer module via direct connections to the applicable lamps. The rear fog lamps and reversing lamps are not directly connected to the lamp units because these lamps must be disabled when the trailer socket is connected.
The LCM communicates with the trailer module via a bi-directional, dedicated serial link. The rear fog lamps and reversing lamps are controlled on this link. The trailer module also uses this link to transmit error messages for the trailer lamps to the LCM.
The trailer module has two modes of operation; sleep mode and normal mode. Sleep mode is initiated by the LCM after a predetermined time. In this mode the trailer module processor clock speed is reduced to a minimum and all loads are switched off to keep current consumption to a minimum. The module operates in normal mode on receipt of an applicable message from the LCM. The required loads and the current supply for bulb failure detection are activated.
The LCM communicates with the trailer module every 2 seconds with a normal mode telegram. If the trailer module no longer responds, the data link to the module is switched low for 1 second after ten unsuccessful attempts to establish the communication. When the LCM switches the data link low, the trailer module is 'reset'. If communication is not established after thirty attempts in succession, the LCM assumes the module is defective and records an applicable error message in the error memory.
If a replacement trailer module is fitted, the LCM instantly recognizes it via the data link. Connection of the Land Rover recommended diagnostic tool is not required to establish communications between the LCM and the trailer module.
CONTROL DIAGRAM - SHEET 1 of 2
NOTE: A = Hardwired connection; B = K bus; D = HS CAN; K = I-Bus; O = LIN Bus.
CONTROL DIAGRAM - SHEET 2 of 2
NOTE: A = Hardwired connection
