Part 1
Exterior Lighting
EXTERIOR LIGHTING - CONTROL DIAGRAM
AUTO HIGH BEAM CONTROL DIAGRAM
CENTRAL JUNCTION BOX (CJB)
The CJB (central junction box) is located behind the rear seat center armrest and is connected to the vehicle wiring harness with 8 multiplugs.
The CJB (central junction box) receives 2 permanent battery power supplies via the BJB (battery junction box).
The lighting circuits are not all protected by conventional fuses as some are protected by Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). The control circuitry within the CJB (central junction box) 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 (central junction box) receives inputs from the following switches:
- Lighting control switch for side lamps, headlamps and auto headlamps
- Momentary push switch for the 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 (central junction box) and switch to ground when operated. The CJB (central junction box) 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 resistive ladder, the output voltage of which is detected by the CJB (central junction box) which in turn determines the selected position.
The CJB (central junction box) 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 CAN (controller area network) bus from the TCM (transmission control module) to enable the CJB (central junction box) to activate the reverse lamps.
The CJB (central junction box) can receive a hazard warning indicator activation message from the RCM (restraints control module), via the high speed CAN (controller area network) bus, in the event of a crash. The CJB (central junction box) 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 (controller area network) bus to the CJB (central junction box) to control the high beam headlamps.
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/LED Monitoring
Bulb/LED (light emitting diode) failure monitoring is performed by the CJB (central junction box) 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 (central junction box) 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 (light emitting diode) is functioning normally, the output signal voltage from the controlling MOSFET is 0V. If a bulb or LED (light emitting diode) 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 (light emitting diode) failure and generates a DTC (diagnostic trouble code) which can be retrieved using an approved Jaguar 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 (light emitting diode)) and checks the bulb or LED (light emitting diode) 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 (central junction box). The CJB (central junction box) 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 (central junction box) detects as unsuccessful bulb illumination.
Alarm Indications
The CJB (central junction box) 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 (restraints control module) to initiate deployment of the airbags, the control module outputs a hazard warning lamps on request on the medium speed CAN (controller area network) bus to the CJB (central junction box). The hazard warning lamps will be activated and will continue until the RCM (restraints control module) outputs a message to deactivate the hazard warning lamps.
Redundant Data Storage
The CJB (central junction box) stores data relating to the Vehicle Identification Number (VIN), total mileage and service interval indicator. This data is received by the CJB (central junction box) from the instrument cluster and used as a back-up in the event of instrument cluster replacement.
If the CJB (central junction box) is to be replaced, an approved Jaguar diagnostic system must be connected to the vehicle and the CJB (central junction box) 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 (central junction box) 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 (restraints control module) requests various electrical operations to assist with the crash situation. The RCM (restraints control module) requests via the bus systems to the CJB (central junction box) to activate the hazard warning lamps.
Security Signal Activation
In the event of the security system being triggered, the CJB (central junction box) requests activation of the hazard warning lamps.
Instrument Panel and Switch Illumination Dimming
The CJB (central junction box) controls the instrument cluster backlighting illumination and also illumination of all instrument panel switches.
The CJB (central junction box) 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 CJB (central junction box) outputs 2 reference voltages to the rotary lighting control switch; one feed being supplied to the lighting function of the switch and the second feed being supplied to the auto headlamp exit delay function. The switch position is determined by CJB (central junction box) by the change in returned signal voltage which is routed through up to 4 resistors in series depending on the selection made.
Lighting functions
OFF - When the lighting control switch is in the off position, the reference voltage flows through 1 of the resistors. The returned signal voltage is detected by the CJB (central junction box) which determines that no lighting selection is made. The reference voltage to the auto headlamp exit delay switch is routed through 4 resistors which is detected by the CJB (central junction box) which determines that auto headlamp or exit delay has not been selected.
SIDE LAMPS - When the lighting control switch is in the side lamp position, the reference voltage flows through 2 of the resistors. The returned signal voltage is detected by the CJB (central junction box) which activates the side lamps. The reference voltage to the autolamp exit delay switch is routed through 4 resistors which is detected by the CJB (central junction box) which determines that auto headlamp or exit delay has not been selected.
HEADLAMPS - When the lighting control switch is in the headlamp position, the reference voltage flows through 3 of the resistors. The returned signal voltage is detected by the CJB (central junction box) which activates the headlamps. The reference voltage to the auto headlamp exit delay switch is routed through 4 resistors which is detected by the CJB (central junction box) which determines that auto headlamp or exit delay has not been selected.
AUTOLAMPS - When the lighting control switch is in the auto headlamp position, the reference voltage flows through 4 of the resistors. The returned signal voltage is detected by the CJB (central junction box) which activates the autolamp function. The reference voltage to the autolamp exit delay switch is routed through 4 resistors which is detected by the CJB (central junction box) which determines that auto headlamp has been selected.
High Beam
The CJB (central junction box) outputs a reference voltage to the LH (left-hand) steering column multifunction switch for operation of the high beam/flash function.
When the switch is in the central off position the reference voltage is passed through 3 resistors. The return voltage is detected by the CJB (central junction box) which determines that no selection has been made.
When the switch is moved forwards to the high beam position, the reference voltage is passed through 2 resistors. The return voltage is detected by the CJB (central junction box) which activates the high beam function of the bi-xenon headlamps.
When the switch is moved rearwards to the high beam flash position, the reference voltage is passed through 1 resistor. The return voltage is detected by the CJB (central junction box) which activates the high beam function of the bi-xenon headlamps for as long as the switch is operated.
Headlamp Delay Functions
EXIT DELAY 1 (30 seconds) - When the lighting control switch is moved to the exit 1 position, the reference voltage from the CJB (central junction box) flows through 3 resistors. The returned signal is detected by the CJB (central junction box) which activates the 30 second headlamp delay timer.
EXIT DELAY 2 (60 seconds) - When the lighting control switch is moved to the exit 2 position, the reference voltage from the CJB (central junction box) flows through 2 resistors. The returned signal is detected by the CJB (central junction box) which activates the 60 second headlamp delay timer.
EXIT DELAY 3 (120 seconds) - When the lighting control switch is moved to the exit 1 position, the reference voltage from the CJB (central junction box) flows through 1 resistor. The returned signal is detected by the CJB (central junction box) which activates the 120 second headlamp delay timer.
Turn Signal Indicators
The CJB (central junction box) outputs a reference voltage to the LH (left-hand) steering column multifunction switch for operation of the LH (left-hand) and RH (right-hand) turn signal indicators.
When the switch is in the central off position the reference voltage is passed through 3 resistors. The return voltage is detected by the CJB (central junction box) which determines that no selection has been made.
When the switch is moved to the LH (left-hand) position, the reference voltage is passed through 1 resistor. The return voltage is detected by the CJB (central junction box) which activates the LH (left-hand) turn signal indicators for as long as the switch is activated or for 3 flashes if the switch was operated for the lane change function.
When the switch is moved to the RH (right-hand) position, the reference voltage is passed through 2 resistors. The return voltage is detected by the CJB (central junction box) which activates the RH (right-hand) turn signal indicators for as long as the switch is activated or for 3 flashes if the switch was operated for the lane change function.
AUXILIARY LIGHTING SWITCH
Rear Fog Lamp Switch
The CJB (central junction box) supplies a reference voltage and return to the rear fog lamp switch. The fog lamp switch is a non-latching, momentary switch.
When the fog lamp switch is off the reference voltage is passed through a 1Kohm resistor. The voltage through the resistor is returned to the CJB (central junction box) which determines that no request for fog lamp operation has been made.
When the driver presses the fog lamp switch, the reference voltage is passed momentarily through a 330 ohm resistor. The change in return voltage is sensed by the CJB (central junction box) which determines fog lamp operation has been requested. The CJB (central junction box) provides a power supply to the 3 LED (light emitting diode)'s in each rear fog lamp. A fog lamp warning lamp in the instrument cluster will also be illuminated when the fog lamps are operating.
The CJB (central junction box) will only activate the rear fog lamps if the headlamps are selected ON or are active with auto headlamp activation. When the headlamps are turned off the fog lamps are also turned off. If the driver presses the fog lamp switch for a second time the rear fog lamps are also switched off. When the headlamps are next switched on, the fog lamps will not be activated until the driver requests fog lamp operation.
NOTE:
The rear fog lamps do not operate when DRL (daytime running lamps) are active.
AUTOMATIC HEADLAMPS
Auto Headlamps
When the lighting control switch is in the auto headlamp position, a reference voltage from the CJB (central junction box) flows through 4 resistors in the lighting control switch. The returned signal voltage is detected by the CJB (central junction box) which activates the autolamp function. The reference voltage to the autolamp exit delay switch is also routed through 4 resistors of the same rating which is detected by the CJB (central junction box) which determines that auto headlamp has been selected.
The rain/light sensor receives a battery voltage output from the ignition relay in the CJB (central junction box). The rain/light sensor continually outputs a LIN (local interconnect network) bus message to the CJB (central junction box) with information regarding the ambient light levels. When the ambient light level reaches a predetermined value, the CJB (central junction box) activates the auto headlamp feature. The CJB (central junction box) can also activate the auto headlamps when it receives information regarding rain fall from the rain/light sensor which subsequently activates the auto wipers function.
Auto High Beam (AHB)
The Auto High Beam (AHB) system is controlled by a AHB control module which is located in the interior rear view mirror body and by the CJB (central junction box). The module and the CJB (central junction box) are connected via the medium speed CAN (controller area network) bus.
The AHB control module receives a power supply from the CJB (central junction box) when the ignition is in power mode 6 (ignition on). The rear view mirror also includes a low resolution camera (image) sensor which detects headlamps and tail lamps of preceding vehicles. The sensor is connected to the control module which evaluates the image data, checking for light intensity and location.
If conditions are correct, the control module will activate the AHB by sending a high or low beam request message to the CJB (central junction box) via the medium speed CAN (controller area network) bus. The CJB (central junction box) then controls the shutter in the Bi-Xenon projector module.
EXTERIOR BULB TYPE/RATING
The following table shows the bulbs used for the exterior lighting system and their type and specification.
NOTE:
The tail lamps, side marker lamps, stop lamps, high mounted stop lamp and rear fog lamps are illuminated by LED (light emitting diode)'s and are non-serviceable components.
