Lighting - Description & Operation Land Rover Range Rover III

Scheme 24

Scheme 25

Scheme 26

General

The exterior lighting is controlled by the Light Check Module (LCM). The LCM controls the following vehicle functions

1. Control and monitoring of exterior lamps including direction indicators and hazard warning functionality
2. Illumination dimmer control of instrument pack and all interior switch illumination
3. Communication and control and monitoring of trailer lighting via the trailer ECU
4. Control of power supply to automatic headlamp levelling ECU (only with bi-xenon headlamps option) (if fitted)
5. Monitoring and evaluation of check control inputs from other system ECU's and output of applicable messages in the instrument pack message center.

The LCM is connected to the I Bus and communicates with other vehicle systems via the instrument pack. The LCM contains a microprocessor which performs the control, monitoring and evaluation functions.

On vehicles from 2005MY, a combined rain/light sensor is fitted which controls the automatic wiper operation fitted to previous models but also controls a new automatic lighting function.

Scheme 27

The LCM is located on the RH 'A' post, behind the trim panel. The LCM is connected to the vehicle wiring harness with three multiplugs.

The LCM receives two permanent battery power supplies via the passenger compartment fusebox and power feeds from the ignition switch positions I (AUX) and II (IGN).

The lighting circuits are not protected by conventional fuses. The control circuitry within the LCM for each individual circuit can detect and isolate a problem circuit.

A monitoring system within the LCM can determine a bulb failure and indicate this to the driver via the instrument pack message center. The following table shows the bulbs monitored by the LCM and their type and rating

Exterior Bulb Type Rating Table

Exterior Bulb Type Rating Table

The bulbs are driven by MOSFETS within the LCM. The LCM provides a Pulse Width Modulation (PWM) output to the front parking lamp and the tail lamp bulbs to protect the bulbs. The PWM output is rapidly switched on and off to provide bulb emulation when a bulb fails.

Input Signals for Lamp Control

The LCM receives inputs from the following switches

1. Lighting switch for side lamps and headlamps
2. Momentary push switches for front and rear fog lamps
3. Steering column switch for direction indicators and main beam/headlamp flash
4. Brake switch
5. Momentary push switch for hazard warning.

The switches are supplied with a 10mA supply from the LCM and switch to ground when operated. The LCM detects that a switch has been operated (ON) when its closing resistance is less than 100O and is detected as OFF when its resistance is more than 10KO.

The LCM also receives ignition switch status via hardwired connections and also on the I and K Bus via the instrument pack.

A reverse gear engaged signal is also received on the I and K bus systems to enable the LCM to activate the reverse lamps. The trailer module also outputs a signal to inform the LCM that a trailer is or is not connected. If a trailer is connected, the LCM transfers control of the trailer reverse lamps and the rear fog lamp to the trailer module.

Via the bus systems the LCM receives a hazard warning lamp activation message from the DCU, via the BCU, in the event of a crash or from the BCU if the alarm system is triggered.

LCM Harness Connector C0937 Pin Details

LCM Harness Connector C0937 Pin Details

LCM Harness Connector C2039 Pin Details

LCM Harness Connector C2039 Pin Details

LCM Harness Connector C2040 Pin Details

LCM Harness Connector C2040 Pin Details

Circuit Protection

Operation of the lamps is performed using overload proof Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). The MOSFETs have a diagnostic output for bulb monitoring and 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 dependent 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.

The brake switch is also monitored by the LCM. If the LCM detects a short circuit to ground in the switch circuit it activates messages to the driver in the message center. These messages will display brake switch defective and LH and RH stop lamp defective. The brake switch is also monitored when the ignition is in position II. The LCM checks the acceleration speed of the vehicle (via bus messages). If the vehicle is accelerating and the brake switch is still active after 10 seconds, the LCM starts a timer. If, after 2 minutes, the brake switch is still active and the vehicle is moving, the LCM activates defective switch messages in the instrument pack message center.

Bulb Monitoring

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

The LCM processor outputs to each MOSFET. This output switches the MOSFET to supply the required output to power the lamp circuit. The microprocessor evaluates the lamp circuits by detecting the returned signals from the controlling MOSFET.

When the bulb is functioning normally, the output signal voltage from the controlling MOSFET is 0V. If a bulb 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 failure and generates a message which is output on the I Bus to the instrument pack. The instrument pack displays the applicable bulb failure message in the message center to provide visual warning to the driver.

Warm monitoring is performed continuously when the lamps are switched on by evaluating the diagnostic output of the MOSFET switches. Cold monitoring is performed at 32 second intervals when the lamps are switched off. The MOSFETs briefly switch on the lamps for approximately 1 millisecond (this is insufficient to illuminate the bulb) and checks the bulb as per warm monitoring.

Cold monitoring is not possible for the dip beam headlamps of vehicles using xenon bulbs. On these vehicles the cold monitoring of the dip beam headlamps is switched off in the LCM. The LCM 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 LCM detects as unsuccessful bulb illumination. The xenon control modules have a diagnostic capability and can store fault related codes.

Alarm Indications

The LCM communicates on the I and K Buses with the BCU to display alarm visual indications for alarm arm, disarm and triggered conditions.

DESCRIPTION

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 DCU to initiate deployment of the airbags, the DCU outputs a hazard warning lamps on request on the K bus to the instrument pack and on the I bus from the instrument pack to the LCM. The hazard warning lamps will be activated and will continue until the DCU outputs a message to deactivate the hazard warning lamps or until the hazard warning lamp switch is pressed.

Redundant Data Storage

The LCM stores data relating to the Vehicle Identification Number (VIN), total mileage and service interval indicator. This data is received by the LCM from the instrument pack and used as a back-up in the event of instrument pack replacement.

If the LCM is to be replaced, T4 must be connected to the vehicle and the replace LCM procedure followed to ensure that the stored data is transferred to the new unit.

DESCRIPTION

Low Voltage Operation

If the battery voltage falls below 11.2V, the LCM operates the minimum lighting to preserve the remaining battery charge.

Scheme 28

The light control switch is located in the fascia between the steering column and the driver's door. The switch comprises a three position rotary switch for controlling side lamps and headlamps, a thumbwheel rheostat which manually controls the fascia and interior switch night illumination, and momentary push switches for front and rear fog lamps. On vehicles from 2005MY with the 'AUTO' headlamp feature, the switch has four positions.

The rotary side and headlamp control switch has three connections to the LCM. One connection supplies a reference voltage to the switch contacts. The two remaining connections supply a combination of earth paths to the LCM for the side lamp, headlamp or 'AUTO' (if fitted) selection contacts.

The front and rear fog lamp switches operate in a similar way, completing earth paths to the LCM 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 LCM.

Automatic Headlamps (Vehicles from 2005MY - If Fitted)

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 WIPERS AND WASHERS for details of the rain/light sensor and automatic wiper operation.

DESCRIPTION

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 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

1. Twilight
2. Darkness
3. Rain
4. Snow
5. Tunnels
6. 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.

Headlamp Assembly

Two headlamps systems are available; Halogen or bi-xenon. The two types of headlamps share a common lens. NAS vehicles use a different lens to other markets but these are also common between the NAS specification halogen and bi-xenon lamps.

Scheme 29

The halogen headlamps use a complex surface reflector for both the dip and main beam lighting units. This type of reflector is divided into separate parabolic segments, with each segment having a different focal length. The reflector segments differ between the dip and main beam lamps to produce the correct beam 'throw' for each lamp.

Both the dip and main beam bulbs are quartz halogen, with a rating of 55W. The bulbs are retained in the headlamp unit with conventional wire retaining clips.

Scheme 30

The Bi-xenon headlamps use a complex surface reflector for the halogen fill in main beam only lighting unit, as used on the halogen headlamp. This type of reflector is divided into separate parabolic segments, with each segment having a different focal length.

The main beam bulbs are quartz halogen, with a rating of 55W. The bulbs are retained in the headlamp unit with conventional wire retaining clips.

The bi-xenon headlamps operate as a dip beam and a main beam headlamp unit. The xenon lamp comprises a projector lens with a solenoid controlled shutter to change the beam output from dip to main beam.

Note. Bi-xenon lamps do not operate when the main beam 'flash' function is operated.

The bi-xenon headlamp system is controlled by the LCM using a control module and igniter located on each headlamp to operate the xenon bulb. The control modules and igniters provide the regulated power supply required to illuminate the xenon bulbs through their start-up phases of operation.

Safety Precautions

The following safety precautions must be followed when working on the xenon headlamp system

Scheme 31

1. DO NOT attempt any procedures on the xenon headlamps when the lights are switched on
2. Handling of the DS2 xenon bulb must be performed using suitable protective equipment, e.g. gloves and goggles. The glass part of the bulb must not be touched
3. Xenon bulbs must disposed of as hazardous waste
4. Only operate the lamp in a mounted condition in the reflector.

The bi-xenon dip/main beam headlamps use ellipsoidal technology for the lens and reflector providing improved night time visibility compared with conventional halogen headlamps. The bi-xenon headlamps provide the following benefits when compared to halogen headlamps

Scheme 32

1. Longer bulb life - Approximately 3 to 5 times longer than a halogen bulb
2. Increased light output - Xenon headlamps output 2.5 to 3 times more lumens than halogen headlamps (lumens is a measure of light energy emitted per second on a given area over a given distance)
3. Blue/white light which simulates natural daylight - Xenon bulbs produce a blue/white light compared to the yellow light produced by a halogen bulb.
4. Improved night time driving visibility - Xenon lamps produce a wider and brighter beam in front of the vehicle than conventional halogen bulbs.
5. Lower operating temperatures
6. Lower power consumption.

The xenon headlamp unit is a self contained unit located within the headlamp assembly. The unit comprises a reflector, an adaptor ring, the lens, a shutter controller and the xenon bulb.

The lens is curved and provides the mounting for the xenon bulb. The bulb locates in two recesses to ensure correct alignment in the reflector and is secured with a retention ring. The retention ring locates over the bulb and is turned clockwise to lock the bulb in the holder. The bulb has a two pin connector which is also a push and turn to lock fitting.

The adapter ring is attached to the reflector and provides for the attachment of the lens. The lens is attached to the adapter ring with an internal spring clip.

The shutter controller is a solenoid which operates, via a lever mechanism, the shutter. The shutter is used to change the beam projection from dip beam to main beam and visa versa.

A beam adjustment mechanism is located between the reflector and the adapter ring. This mechanism rotates to blank off a portion of the beam spread to enable the vehicle to be driven in opposite hand drive markets without applying blanking decals to the headlamp lens. The beam is changed by removing the access cover at the rear of the lamp assembly and moving a small lever located near the bulb holder, at the side of the reflector.

Crash Signal Activation

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

Security System Activation

In the event of the security system being triggered, the BCU requests activation of the hazard warning lamps. In some markets the low beam and/or high beam headlamps can also be activated.

Headlamp Levelling (Xenon headlamps only) - If fitted

The automatic headlamp levelling system automatically adjusts the vertical positioning of the headlamps to provide the optimum headlamp beam position for maximum driving visibility and preventing glare to oncoming drivers.

Note. The headlamp levelling system is not fitted to later vehicles. The headlamp levelling motors, headlamp levelling ECU and the levelling specific height sensors are not fitted to these vehicles. Headlamp levelling on these vehicles is performed by the air suspension.

The system is controlled by an automatic headlamp levelling ECU located at the bottom of the LH 'A' post. The ECU is connected to and receives information from the Hall effect front and rear height sensors which are also used by the air suspension system. The ECU also receives a signal from the ABS ECU for vehicle acceleration. The ECU has diagnostic capabilities and can communicate with T4 via the K Bus, the instrument pack and the DS2 Bus.

The levelling system is a fast response system which reacts to changes of vehicle angle when driving. The ECU receives vehicle speed signals from the ABS ECU and a brake switch signal from the LCM. These two signals are used to adjust the headlamp position to compensate for changes in vehicle attitude due to acceleration or braking.

Stepper motors, located as part of the headlamp unit, drive a threaded rod which moves the lower edge of the headlamp forward or backwards to adjust the vertical position of the headlamp beam. The stepper motors are controlled by the ECU which, using the data from the height sensors, determines the attitude of the vehicle and compensates for load differences at the rear of the vehicle or changing driving conditions.

Scheme 33

The front side and direction indicator lamp assemblies are located outboard of each headlamp assembly. The direction indicator bulbs are 21W bayonet fitting and the side lamp bulbs are 5W bayonet fittings.

The lamp assembly is retained by two integral plastic clips which locate in the headlamp assembly housing. A threaded shaft locates in a hole in the adjacent wing panel. A knurled nut is and washer is fitted to the threaded shaft and positively retains the lamp assembly in position. The knurled nut allows for the lamp assembly to be moved in or out providing adjustment to ensure flush alignment with the wing contour.

The direction indicator and side lamp bulbs are located in holders. The holders are secured in the lamp housing by rotating through 90°. Each holder has a connector to allow for connection to the electrical harness.

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.

Scheme 34

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°. The holder has a connector to allow for connection to the electrical harness.

Scheme 35

The rear side and direction 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 prised 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 brake lamp and the direction indicator. The brake 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 brake lamp in a red colour. The direction indicator lamp is located behind the brake lamp LED unit. The bulb is located in a reflector unit which emits the direction indicator light around the outer diameter of the brake lamp LED assembly.

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 a 21W bulb in the lower half of the aperture. 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 21W/5W bulb. 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.

Scheme 36

The side repeater lamps are located in the front wings, forward of the louvred air vents. The side repeater lamps are clipped into the wing aperture and can be removed by pushing forwards and pulling outwards from the wing.

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

Hazard Warning Lamps

The hazard warning lamps use the front and rear direction indicator lamps as previously described. These are controlled by the LCM in response to a hazard warning lamp request from the fascia switch.

In the event of an accident of a severity to activate and deploy the airbags, the DCU requests various electrical operations to assist with the crash situation. The DCU requests via the bus systems to the LCM to activate the hazard warning lamps. These will continue to operate until deselected using the fascia switch. The lamps flash at a frequency which is the same as the frequency used to flash the headlamp main beam in the same situation.

Reverse Lamps

The reverse lamps are located in the lower tail door and positioned at either side of the number 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 reverse lamp uses a 6W bayonet type bulb. The LCM monitors the bulbs and, if a failure is detected, alerts the driver via the instrument pack message center.

Number Plate Lamps

Two number plate lamps are located in the trim above the number 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 pack message center.

Daylight Running Lamps (selected markets only)

In markets which require daylight running lamps, the LCM is programmed with coding which activates the dip beam or dimmed main beam headlamps when the ignition is in position II.

Daylight running lamps can only be switched on or off using T4 providing the LCM is not coded with a country specific code.

Canadian market vehicles use the main beam headlamps with a dimmed output of 5.5 to 6.0V, controlled by the LCM. Also, on Canadian vehicles with bi-xenon lamps, only the halogen main beam lamp is illuminated using a reduced voltage of 5.5 to 6.0V. All other countries using daylight running lamps (Finland, Norway and Sweden) use the full power dip beam headlamps.

Scheme 37

The main beam/direction indicator column control switch is located on the left hand side of the steering column and controls the following functions

1. Headlamp dip/main beam
2. Headlamp main beam flash
3. Left/right direction indicators
4. Trip computer functions. «DESCRIPTION»(/land-rover/range-rover/iii-2002-2005/remont/exterior-lights/#lighting-description-operation) The main 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 direction indicators. The LCM senses the resistance on the ground wire and determines which function has been selected.

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 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 reverse lamp and rear fog lamp operation and overload proof MOSFET circuit breakers for the following lamps

1. Left direction indicator
2. Right direction indicator
3. Brake lamps
4. Left tail lamp
5. Right tail lamp
6. 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 reverse 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 reverse 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 T4 is not required to establish communications between the LCM and the trailer module.

Trailer module Harness Connector C0380 Pin Details

Trailer module Harness Connector C0380 Pin Details

Instrument Panel and Switch Illumination Dimming

The LCM controls the instrument pack backlighting illumination and also illumination of all switches.

The LCM 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 light control switch is in the side lamp or headlamp position.

Scheme 38

The diagnostic socket allows for the transfer of information between the LCM, the automatic headlamp levelling ECU and T4. The diagnostic socket is located in the fascia, in the driver's stowage tray. The socket is secured in the fascia and protected by a hinged cover.

The LCM has diagnostic capabilities and store fault codes relating to the lighting systems. The xenon control modules cannot be interrogated via the LCM, but the LCM incorporates xenon specific diagnosis up to the control modules.

The xenon control modules, located on the rear of the headlamp assemblies, can be interrogated using T4 for faults relating to the operation of the xenon lamps. The control modules are connected on a DS2 link to the diagnostic socket.

The following information describes the functionality of the individual light circuits. The control of the circuits is performed by coding data in the LCM EEPROM. This coding is programmed on the production line and some coding for lamp functionality is country specific.

Direction Indicator and Hazard Warning Lamps

With the ignition switch in position I or II, the direction indicators can be operated. When the column switch is moved to the left or right direction position the direction indicator lamps are activated with a pulse rate of 640 milliseconds and a pulse duty factor of 50:50. If the operation is in the illuminated phase and the direction indicator is switched off, the flashing phase will end. If the switch position is rapidly moved from the left position to the right position (or visa versa), the applicable direction indicator lamps are switched over immediately.

If one of the vehicle or trailer direction indicator bulbs, with the exception of the side repeater lamps, is defective, the flashing frequency is doubled.

If the ignition is in position I or II and a left or right direction indicator is active, depressing the hazard warning switch will operate the hazard warning lamps, overriding the direction indicator function. when the hazard warning lamp switch is pressed a second time, the hazard warning lamp function is deactivated and the direction indicator operation reinstated, if still selected on.

If the ignition is in position I or II and the hazard warning lamps are active, operating the column switch for the left or right direction indicators will suspend the hazard warning lamp operation and activate the selected direction indicator. When the direction indicator column switch is moved to the off position, the hazard warning function will be reinstated.

If the hazard warning lamps have been activated by an I and K Bus message to the LCM in response to a crash detection, the hazard warning lamps can be switched off using the hazard warning lamp switch. If the hazard warning lamps have been activated by the BCU due to an anti-theft alarm trigger, the hazard warning lamps can only be switched off by a deactivate message from the BCU. The hazard warning lamps will also deactivate after 5.5 minutes.

The direction indicator warning lamps and the direction indicator sound are controlled by the instrument pack. They are activated by the instrument pack on receipt of a lamp status message from the LCM. The direction indicator warning lamps and the sounder are synchronized with this message with the direction indicator lamp illumination frequency.

Parking Lamps

The parking lamp function is controlled using the direction indicator column switch. If the ignition is off and the direction indicator switch is moved to the left or right position, the selected parking lamps will be illuminated. The front parking lamp is illuminated, along with the top bulb in the rear tail lamp. On NAS vehicles the applicable side marker lamps are also illuminated. The number plate lamps and the lower bulb in the tail lamp for the selected side are deactivated. No instrument pack or fascia illumination is activated. If the ignition is on and the direction indicator switch is in the left or right position, the selected side lamps will not be activated when the ignition is subsequently switched off.

Side Lamps

If the light control switch is in the side lamp or headlamp position, the front side lamps and rear tail lamps are activated. Both the upper and lower tail lamp bulbs are active along with the number plate lamps. On NAS vehicles, the side marker lamps are also active.

The instrument pack and fascia illumination remains illuminated at the brightness determined by the position of the dimmer control.

Light Control Switch Illumination

When the ignition is in position I or II, the switch legends on the light control switch are illuminated at maximum brightness when the light control switch is in the 'O' (off) position. When the light control switch is rotated to the side or headlamp position the legend illumination is dimmed.

Low Beam Headlamps

The low beam headlamps are activated when the light control switch is in the headlamp position and the ignition is in position II.

High Beam Headlamps

The main beam headlamps are activated when the light control switch is in the headlamp position and the ignition is in position I or II. Moving the column switch forwards from the low beam position activates the main beam headlamps.

When the ignition is in position I or II and the column switch is moved rearwards to the headlamp flash position, the main beam lamps are activated for as long as the switch is held in this position.

If the vehicle is involved in an accident and the airbags are deployed, the crash message from the DCU also illuminates the main beam headlamps which flash at the same frequency as the hazard warning lamps.

The functionality of the main beam differs between halogen only and bi-xenon and halogen headlamps. This is shown in the following table

LIGHT CONTROL SWITCH POSITION CHART

Xenon Headlamps

The xenon bulbs illuminate 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. The Xenon gas reacting to the controlled current flow between the electrodes produces the blue/white light.

To operate at full efficiency, the xenon bulb go through three phases of operation before full output for continuous operation is achieved. The three phases are; starting phase, warm-up phase and continuous phase.

In the start-up phase the bulb requires an initial high voltage starting pulse of 18000 to 28000 volts to establish the arc. This is produced by the igniters. The warm-up phase begins once the arc is established. The 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 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 xenon system is controlled by the LCM, two control modules and two igniters. The control modules (one per headlamp) receive an operating voltage from the LCM when the headlamps are switched on. The control modules regulate the power supply required through the phases of start-up. The control modules also have diagnostic capability which can be accessed using T4 via the diagnostic socket.

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

Front Fog Lamps

The front fog lamps are only active with the ignition switch in position II and the light control switch in the side lamp or headlamp position. When the ignition is switched off, the fog lamp selection is automatically deselected.

Rear Fog Lamps

The rear fog lamps are only active with the ignition switch in position II. With the light control switch in the side lamp position, the rear fog lamps can only be selected on when the front fog lamps are active. If the front fog lamps are subsequently switched off, the rear fog lamps are automatically deselected.

With the light control switch in the headlamp position, the rear fog lamps can be activated individually, irrespective of the front fog lamp status.

Brake Lamps

The brake lamps are active with the ignition switch in positions I or II. The LCM receives an input from the brake switch which is used as a signal to activate the brake lamps. When HDC is active, the ABS ECU outputs a signal on a separate hardwired connection to the LCM to activate the brake lamps when the HDC function is operating.

The reverse lamps will operate with the ignition switch in position II. The LCM activates the reverse lamps on receipt of an message on the I Bus that reverse gear has been engaged.

Main Beam Direction Indicator Column Control Switch

Moving the switch rearwards, towards the driver, completes a ground path to the LCM. The ground path is completed through a 1.2kO resistor which is sensed by the LCM. On receipt of this signal, the LCM activates the main beam headlamps for as long as the switch is operated. This position is non-latching and operates with the ignition switch in position I, but without the side lamps or headlamps being switched on.

Moving the switch forwards, into a latching position, completes a ground path to the LCM. The ground path is completed through a 300O resistor which is sensed by the LCM. On receipt of this signal, the LCM activates the main beam headlamps. The main beam will remain active until the switch is moved rearwards again, removing the ground path. This function only operates when headlamps are selected on with the light control switch and the ignition switch is in position II.

Moving the switch upwards or downwards completes a ground path to the LCM. The ground path is completed through a 1.2kO resistor for the RH direction indicator or through a 300O resistor for the LH direction indicators which is sensed by the LCM. On receipt of this signal the LCM activates the RH or LH direction indicators. The switch is a latching switch, although the direction indicators can also be operated by lightly pushing the switch without engaging the latch. The direction indicators will remain active until the switch is moved to the central off position. The direction indicators operate with the ignition switch in position I.

With the ignition switched off, this switch position also operates the selected side parking lamps. Refer to ' PARKING LAMPS ' operation for details.

Automatic Headlamp Levelling (Xenon headlamps only) - If fitted

If fitted, the automatic headlamp levelling is only used on vehicles fitted with xenon headlamps. When the LCM detects that the ignition is in position II and the side lamps or headlamps have been selected on using the light control switch, the headlamp levelling control is activated. The headlamp levelling control is also activated when the LCM receives an 'engine running' signal on the I Bus, irrespective of the light control switch position.

When initially activated, the automatic headlamp levelling ECU cycles the stepper motors through their full range of adjustment and stops at a default position. The ECU monitors the air suspension height sensor signals to determine the vehicle angle and adjusts the headlamps accordingly. As the vehicle is driven, the ECU continuously monitors the signals from the front and rear RH level sensors and also uses the speed and brake signals to determine the operation. The ECU filters rapid changes of signals from the height sensors to prevent unnecessary adjustment.

Headlamp Delay

The LCM controls a headlamp delay function which illuminates the driveway after leaving the vehicle. The headlamp delay will operate on dipped beam headlamps only regardless of the position of the column stalk switch.

The delay is operated when the ignition is switched off and the key removed with the headlamps switched on. The message center displays a 'HEADLIGHTS ON' message accompanied by a chime from the sounder. When the light control switch is moved to the 'off' position, the message center displays a 'HEADLIGHT DELAY' message and the dip 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.

On vehicles from 2005MY with automatic headlamps feature fitted, the operation of the headlamp delay is as described above if the light control switch is not in the 'AUTO' position. If the light 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 main beam/indicator column control 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 Pack Warning Lamp Illumination

The warning lamps in the instrument pack for left and right direction indicator, front and rear fog lamps and headlamp main beam are activated by the LCM via messages to the instrument pack on the I Bus. The synchronization of the indicator warning lamps with the external lamp frequency is controlled by a cyclic transmission of the light status on the I Bus.

The automatic headlamp function is controlled by the LCM on receipt of messages from the rain/light sensor. When the light control switch is in the 'AUTO' position the exterior lights are controlled according to the ambient light levels and weather conditions.

The rain/light sensor measures the ambient light and if the available light level falls below a pre-determined level, a message is sent, via the instrument pack to the LCM to activate the exterior lamps. If the rain/light sensor detects deteriorating weather conditions, such as rain, snow, fog etc. the exterior lights will be activated and the wipers will also be activated accordingly.

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.

Scheme 39

Scheme 40

The interior lighting is controlled by the Body Control Unit (BCU) which is located below the front passenger seat. The interior lighting comprises the following lamps

1. Front interior lamp unit
2. Rear interior lamp unit
3. Upper tail door load space lamps (2 off)
4. Luggage compartment load space lamp
5. Fascia mounted sill lamps (2 off)
6. Under fascia footwell lamps (2 off)
7. Door mirror approach lamps (2 off)
8. Puddle lamps (4 off).

The interior lamps have two modes of operation; automatic or manual. In the automatic mode the interior lamp functionality is controlled by the BCU on receipt of various input signals. In manual mode, the lamps can be switched on and off using the momentary button adjacent to the front interior lamp or can be disabled completely using the same switch.

Note. The LED illumination of the front door pockets and the front and rear interior door handles is a function of the LCM and only operates when the light control switch is in the side lamp or headlamp positions.

The following table shows the bulbs used for the interior lighting and their type and rating

BULB RATING CHART

Front and Rear Interior Lamps and Map Reading Lamps

The front and rear interior lamp assemblies are similar in design. The front interior lamp switch is connected directly to the BCU and controls the manual operation of the interior lamp functionality. The rear interior lamp switch is used only to switch the lamp on and off.

The map reading lights have a non-adjustable beam and are controlled via separate switches. Both the interior and map reading lamps use capless 5W bulbs.

Luggage Compartment Lamps

The luggage compartment lamps comprise one lamp unit located on the RH side trim panel, adjacent to the auxiliary power socket, and two lamps located in the interior trim panel of the upper tail door. All of these lamps are of the same design and use capless 5W bulbs. The lamps are controlled by the BCU and operate on the automatic interior lamp functionality.

Glovebox Lamp

The glovebox lamp is located inside the glovebox, at the top, adjacent to the latch. The lamp comprises a festoon 5W bulb. The lamp housing also incorporates a plunger type switch which is activated to switch the lamp on when the glovebox lid is opened.

Vanity Mirror Illumination Lamps

The vanity mirror lamps are located behind a hinged cover, either side of the mirror glass. A festoon type bulb is fitted in contacts behind each lamp lens. The lamps are activated by a simple switch which operates when the mirror cover is lifted.

Footwell Lamps

Two types of footwell lamps are fitted. Two directional sill lamps are located in the front of the fascia and illuminate the sill area. These lamps use 3W capless bulbs.

Two further footwell lamps are located in the lower fascia closing panels and illuminate the area below the fascia. These lamps use 5W capless bulbs. The lamps are controlled by the BCU and operate on the automatic interior lamp functionality.

Door Puddle Lamps

Each of the doors is fitted with a puddle lamp to illuminate the ground below the door when the door is open. The front door puddle lamps are located in the lower face of the door, facing the ground. The rear door puddle lamps are located in the bottom of the door trim panel.

The puddle lamps use a capless 5W bulb. The puddle lamps are controlled by the BCU and operate on the automatic interior lamp functionality.

Door Mirror Approach Lamps

The exterior mirror housings are fitted with a lamp which illuminates the area below the front door. The approach lamps comprise a housing located inside the mirror and bulb holder with harness connector. The housing contains a plastic lens which directs a beam of light in the required area. The approach lamps use a capless 6W bulb.

The lamps are controlled by the BCU, via a dedicated relay which is located at the rear of the passenger compartment fusebox.

Diagnostics

Diagnostics for the interior lamps is limited to a check of the function of the front interior lamp switch. The BCU can be interrogated using T4 to establish the correct operation of the front interior lamp switch, the door switches and the tail door switches.

DESCRIPTION

The interior lamp operation is activated by any of the following input signals

1. Door switch contacts (front and rear)
2. Ignition switch position I (Aux)
3. Central locking, lock request
4. Central locking remote handset operation
5. Crash sensor
6. Front interior lamp switch.

The load space lamp and the upper tail door lamps are not switched on with the interior lamps. These lamps are only activated when the upper tail door is opened. When the upper tail door is opened, the interior lamps, in addition to the load space lamps, are switched on and are subject to the BCU timers.

Automatic Operation

The automatic control of the interior lamps has several switch on and off conditions as follows

1. The interior lamps are switched on when one or more doors are opened. When all the doors are closed, the interior lamps are switched off after a delay of 20 seconds. If the vehicle is locked after closing the doors, within the 20 second period, the lamps go off immediately.
2. When the interior lamps are on and the ignition is moved to positions I or II, the lamps go off immediately after all doors have been closed.
3. When the ignition switch is moved to the off position, the interior lamps are switched on for 20 seconds. This timer is overridden if a door is subsequently opened.
4. When the vehicle is unlocked and the doors are closed, the interior lamps can be activated for a further 20 second period by pressing the 'unlock' button on the remote handset.
5. When the vehicle is unlocked from a locked condition, the interior lamps are activated for a 20 second period. This timer is overridden if a door is subsequently opened.
6. If a door is left open, the interior lamps will remain on for 16 minutes. After this period, the BCU timer switches the interior lamps off to prevent excessive battery drain.

The BCU uses a PWM operation of the interior lamps for the on/off conditions. The lamps are switched on with a 'soft ramp' of 1.3 seconds. The lamps are switched off with a 'soft ramp' of 2.6 seconds. The soft on/off operation is controlled by a semiconductor within the BCU.

Manual Operation

The interior lamps can be switched on or off using the manual switch for the front interior lamp. The front interior lamp switch will switch all interior lamps, front and rear, on or off. If the interior lamps are on when the switch is pressed, all interior lamps will go off. The on and off automatic switching conditions remain effective even when the manual switch is used.

If the ignition switch is in position I or II and the front interior lamp switch is used to switch the interior lamps on, the lamps will remain on continuously while the ignition is in position I or II. If the ignition switch is moved to the off position, the interior lamps will be subject to the 16 minute BCU timer. The interior lamp is immediately switched off when the vehicle is locked. After a locking procedure, the interior lamp automatic control is reinstated.

The rear interior lamp switch will switch the rear interior lamp only on or off.

Continuous Off

To prevent drain on the battery if the doors are to remain open for some time, the interior lamps can be turned off permanently. This is stored in the BCU EEPROM and is also activated following a system power down or a reset of the BCU.

To enter the continuous off condition, the front interior lamp switch must be pressed and held for more than 3 seconds. The continuous off function can only be disabled by pressing the front interior lamp switch, after which, full automatic control is resumed. When continuous off is active, the rear interior lamp switch can still be used to switch the rear interior lamp only on or off.

Crash Signal Operation

The BCU receives a crash signal on a hardwired connection from the DCU in the event of a crash of a severity to activate the airbags. On receipt of this signal, the BCU activates the interior lamps which are on permanently and not subject to the BCU timer.

The crash operation of the interior lamps can only be cancelled by operating the manual switch on the front interior lamp or by locking and unlocking the vehicle.

See also:
• WIPERS AND WASHERS
• DESCRIPTION
• PARKING LAMPS