Hazard Warning Lamps: Description and Operation

Turn Signal Indicators And Hazard Flashers

DESCRIPTION

Turn Signal Indicators
Operation of the turn signal indicator lamps is controlled by the Central Junction Box (CJB) via the LH steering column multi-function switch. Moving the column switch downward will illuminate the LH indicators. Moving the switch upwards will illuminate the RH indicators. A tell-tale lamp within the instrument cluster will flash (380 ms on, 380 ms off) when the turn signal indicators are operational.

If a front or rear indicator bulb fails, the flash rate of the tell-tale lamp will double. The flash rate of the external lamps will remain the same.

If the CJB detects a trailer is fitted, it will flash the trailer tell-tell lamp located in the instrument cluster at the same frequency as the turn signal indicator tell-tale lamps. If a trailer bulb fails, the trailer tell-tale lamp will not flash.

Hazard Flashers
Operation of the hazard flashers is via the non-latching switch located at the top of the instrument panel center switch pack. When the hazard flashers are selected, any turn signal indicator request will be overridden and all LH and RH bulbs will flash. Functionality is the same as that for the turn signal indicator lamps.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fusible link 11E and fusible link 16E of the Battery Junction Box (BJB) (C0632) on an R wire. Fusible link 16E (C0570) provides a constant battery feed to the CJB, the RH indicator Field Effect Transistor (FET), and the LH indicator FET on an NG wire. Both FETs are located in the CJB (C0583) and are provided a ground (C0585) on a B wire.

Fusible link 11E (C0570) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is in the ignition position, current flows across the switch (C0028) to the CJB (C0582) on a Y wire.

Steering Column Multi-function Switch
The CJB (C0580) is connected to the LH steering column multi-function switch (C1393) by GW and GR wires. If the column switch is moved to the LH turn position, the switch contacts close and allow the feed supplied by the CJB on the GR wire to flow to ground on a B wire. If the multi-function switch is moved to the RH turn position, the switch contacts close and allow the feed supplied by the CJB on the GW wire to flow to ground on a B wire.

RH Turn
If a RH turn is requested via the LH steering column multi-function switch, the CJB provides a pulsed signal feed to the RH indicator FET. The RH indicator FET (C0585) will now provide a pulsed feed to the RH rear turn signal indicator bulb (C0125) on a GW wire and the RH side repeater (C0012 on LHD vehicles, C0013 on RHD vehicles) on a GW wire (GW then GR on RHD vehicles). Both lamps are provided a ground on B wires.

The RH indicator FET (C0583) also provides a pulsed feed to the RH front turn signal indicator bulb (C0011) on a GW wire. The bulb is provided a ground on a B wire.

LH Turn
If a LH turn is requested via the LH steering column multi-function switch, the CJB provides a pulsed signal feed to the LH indicator FET. The LH indicator FET (C0585) will now provide a pulsed feed to the LH rear turn signal indicator bulb (C0121) on a GR wire and the LH side repeater (C0013 on LHD vehicles, C0012 on RHD vehicles) on a GR wire (GR then GW on RHD vehicles). Both lamps are provided a ground on B wires.

The LH indicator FET (C0583) also provides a pulsed feed to the LH front turn signal indicator bulb (C0009) on a GR wire. The bulb is provided a ground on a B wire.

Hazard Flashers
The CJB (C0580) monitors the condition of the hazard flasher switch (C2387) by providing a feed on an LGR wire. If the switch is pressed, the switch contacts close and a ground path is created on a B wire. Sensing this momentary earth, the CJB provides a pulsed signal feed to both the LH and RH FETs simultaneously. The FETs operate in the same way as described previously.

Instrument Pack
The CJB (C0580) informs the instrument pack (C0230) which tell-tale lamp to illuminate via the medium speed CAN bus on YU (high) and YW (low) wires.