Headlamps

Headlamps

DESCRIPTION

Introduction
Three headlamp systems are available; Halogen, Xenon, and Adaptive Front lighting System (AFS). Operation of all three systems is controlled by the Central Junction Box (CJB). The headlamps can be switched on by turning the lighting control switch located on the instrument panel, adjacent the steering wheel. Turning the switch to the first position will illuminate the side lamps; turning it to its second position will illuminate the headlamps; turning it to its third position will activate the AFS (if fitted).

The LH steering column multi-function switch is used to switch the headlamps from low to high beam. The switch sits in one of two positions. The forward position will initiate high beam operation, the rear position will initiate low beam operation.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to the following on an R wire:
^ Fuse 25E
^ Fusible link 11E
^ Fusible link 15E
^ Fusible link 16E.

All are located in the Battery Junction Box (BJB) (C0632).

Fuse 25E (C0570) provides a constant battery feed to the lighting control switch (C0041) on an NG wire. Fusible link 15E (C0570) provides a constant battery feed to the switch contacts of the side lamp relay on an NG wire. The side lamp relay is located in the Central Junction Box (CJB) (C0583).

Fusible link 16E (C0570) provides a constant battery feed to the following on an NG wire:
^ The RH low beam Field Effect Transistor (FET)
^ The RH high beam FET
^ The side lamp relay coil
^ The LH low beam FET
^ The LH high beam FET
^ The CJB.

All are located within the CJB (C0583).

Fusible link 11E (C0570) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is in the 'auxiliary' position, current flows across the switch (C0028) to fuse 18P of the CJB (C0582) on a W wire. Fuse 18P (C0585) provides an auxiliary ignition feed to the rain/ambient light sensor (C0961) on a G wire.

When the ignition switch is in the 'ignition' position, current flows across the switch (C0028) to fuse 62P and 67P of the CJB (C0582) on a Y wire. Fuse 62P (C0582) provides an ignition feed to the lighting control switch (C0041) on an NP wire. Fuse 67P provides a feed to the automatic lighting relay, which is also located in the CJB.

Side Lamps
When the lighting control switch is turned to the side lamp position, current flows across the switch (C0041) to the CJB (C0580) on an RW wire. The CJB will now energise the side lamp relay by providing a ground path for the relay coil. The energised side lamp relay provides a feed to fuse 2P and fuse 4P, which are also located in the CJB.

Fuse 2P (C0585) provides a feed to the RH tail lamp unit (C0125) on an RO wire. Fuse 2P (C0583) also provides a feed to the RH side lamp (C0011) on an RO wire.

Fuse 4P (C0585) provides a feed to the LH tail lamp unit (C0121) and the number plate lamps (C1495) on RB wires. Fuse 4P (C0583) also provides a feed to the LH side lamp (C0009) on an RB wire.

All lamps are provided a ground on B wires.

Headlamps

Steering Column LH Multi-function Switch
The CJB (C0580) monitors the condition of the steering column multi-function switch (C1393) by supplying two reference feeds; one on a UR wire, one on a UW wire. When the column switch is in the low beam position, the switch contacts are open. As the CJB doesn't register a ground path, it initiates low beam operation by providing a signal feed to the LH and RH low beam FETs.

When the column switch is pushed forward to the main beam position, the switch contacts close. Current flows across the switch to ground on a B wire. The CJB (C0580) registers the ground path via the UR wire and instigates main beam operation by providing a signal feed to the LH and RH high beam FETs.

If the column switch is pulled back to the main beam flash position, the CJB (C0580) will register a ground path via the UW wire and will instigate high beam operation as described previously. When the switch is released, the CJB will revert back to the previous lighting state.

The multi-function switch (C1393) is provided a ground path on a B wire.

Low Beam
When the lighting control switch is turned to the headlamp position, current flows across the switch (C0041) to the CJB (C0580) on a Y wire. With the steering column multi-function switch in the low beam position, the CJB provides a signal feed to the LH low beam FET, and the RH low beam FET. Both are located in the CJB and are provided a ground (C0585) on a B wire.

The LH low beam FET (C0583) provides a feed to the LH low beam bulb (C0009) on a UK wire. The RH low beam FET (C0583) provides a feed to the RH low beam bulb (C0011) on a UO wire. Both are provided grounds on B wires.

Main Beam
When the lighting control switch is turned to the headlamp position, current flows across the switch (C0041) to the CJB (C0580) on a Y wire. With the steering column multi-function switch in the main beam position, the CJB provides a signal feed to the LH main beam FET, and the RH main beam FET. Both are located in the CJB and are provided a ground (C0585) on a B wire.

The LH main beam FET (C0583) provides a feed to the LH main beam bulb (C0009) on a US wire. The RH main beam FET (C0583) provides a feed to the RH main beam bulb (C0011) on a UB wire. Both are provided grounds on B wires.

Automatic Headlamps
When the lighting control switch is turned to the 'Auto' lighting position, current flows across the switch (C0041) to the CJB (C0580) on an R wire. When the CJB receives this feed it initiates the Automatic Headlamp system. The CJB (C0586) interprets messages sent from the ambient light sensor (C0961) via the Local Interconnect Network (LIN) on an R wire. If the ambient light levels are below a pre-set level, the CJB will automatically illuminate the headlamp low beam bulbs and the tail lamps.