Operation

Direction Indicator Lamps Operation
The BCU supplies a reference voltage from pin C0663-2 on a GR wire for the LH flasher and from pin C0660-6 on a GW wire for the RH flasher. When the flasher switch is moved to the LH or RH hand flasher position an earth path is completed from the switch on a B wire via header C0286 LHD/C0291 RHD to earth header C0018 LHD/C0017 RHD. The completion of the earth, signals the BCU that a request for LH or RH flasher operation has been made.

The BCU then sends a signal on an SK wire from pin C0661-1, via header C0293 LHD/C0292 RHD, to the IDM in the passenger compartment fusebox The SK wire is the serial data bus between the BCU IDM and the instrument pack.

The signal is received by the IDM and interpreted as a request for LH or RH flasher operation. The IDM grants an earth path for the coil of the LH or RH direction indicator relay. The coil is energised by the feed from fuse 14 in the engine compartment fusebox, closing the relay contacts.

With the contacts closed, the feed from fuse 14 also passes through the relay and is connected, via a resistor, from the passenger compartment fusebox to the applicable direction indicator. The IDM controls the flasher operation by momentarily removing and restoring the earth for the relay coil, which opens and closes the contacts causing the indicator bulbs to flash on and off.

The resistor is used by the IDM to monitor the current drawn through the resistor by the direction indicator bulbs. If an indicator bulb fails the IDM detects the drop in current draw across the resistor and operates the flasher relay at a faster speed. The faster flash is also transmitted to the instrument pack to inform the driver of the bulb failure.

The IDM operates the direction indicator lamps in the instrument pack on the serial data bus on the SK wire from the passenger compartment fusebox via header C0293 LHD/C0292 RHD to the instrument pack.

The direction indicators are connected from the passenger compartment fusebox as follows:

LH front, rear and side direction indicator/hazard warning lamps
The feed from the LH direction indicator relay is connected on a GR wire from the passenger compartment fusebox to header C0289.

LH front
The feed is connected from header C0289 on a GR wire to the LH front direction indicator/hazard warning lamp. The lamp is connected on a B wire, via header C1001 LHD/C0288 RHD, to earth eyelet connector C0564-1 LHD or earth header C0017 RHD.

LH rear
The feed is connected from header C0289 via header C0295 on a GR wire to the LH rear direction indicator/hazard warning lamp. The lamp is connected on a B wire to earth header C0707.

LH Side repeater
The feed is connected from header C0289 on a GR wire to the LH front side repeater lamp. The lamp is connected on a B wire, via header C0288, to earth header C0017.

Trailer connection
The feed for the trailer connection is taken from header C0289, via header C0295, on a GR wire to the trailer pick-up. The trailer pick-up is connected on a B wire to earth eyelet connector C0808-1.

RH front, rear and side direction indicator/hazard warning lamps
The feed from the RH direction indicator relay is connected on a GW wire from the passenger compartment fusebox to header C0289.

RH front
The feed is connected from the header C0289 on a GW wire to the front RH direction indicator/hazard warning lamp. The lamp is connected on a B wire, via header C1000 to earth eyelet connector C0558-1.

RH rear
The feed is connected from header C0289, via header C0723, on a GW wire to the RH rear direction indicator/hazard warning lamp. The lamp is connected on a B wire to earth header C0706.

RH Side repeater
The feed is connected from header C0289 on a GW wire to the RH RH front side repeater lamp. The lamp is connected on a B wire, via header C1000, to earth eyelet connector C0558-1.

Trailer connection
The feed for the trailer connection is taken from header C0289, via header C0723, on a GW wire to the trailer pick-up. The trailer pick-up is connected on a B wire to earth eyelet connector C0808-1.

Hazard Warning Lamps Operation
The BCU supplies a reference voltage from pin C0663-12 on a GR wire to the hazard warning switch. When the hazard warning switch is operated an earth path is completed from the switch on a B wire, via header C0760, to earth header C0018 LHD/C0017 RHD. The completion of the earth signals the BCU that a request for hazard warning lamp operation has been made.

The BCU then sends a signal on an SK wire from pin C0661-1, via header C0293 LHD/C0292 RHD, to the IDM in the passenger compartment fusebox. The SK wire is the serial data bus between the BCU, IDM and the instrument pack.

The signal is received by the IDM and interpreted as a request for hazard warning lamp operation. The IDM grants an earth path for the coils of the LH and RH direction indicator relays. The coils are energised by the feed from fuse 14 in the engine compartment fusebox, closing the relay contacts.

With the contacts closed, the feed from fuse 14 also passes through the relays and is connected, via resistors, from the passenger compartment fusebox to the direction indicators. The IDM controls the flasher operation by momentarily removing and restoring the earth for the relay coils, which opens and closes the contacts causing the indicator bulbs to flash on and off.

The resistor is used by the IDM to monitor the current drawn through the resistor by the direction indicator bulbs. If an indicator bulb fails, the IDM detects the drop in current draw across the resistor and operates the flasher relay at a faster speed. The faster flash is also transmitted to the instrument pack to inform the driver of the bulb failure.

The IDM operates both direction indicator lamps in the instrument pack on the serial data bus on the SK wire from the passenger compartment fusebox, via header C0293 LHD/C0292 RHD, to the instrument pack.

The hazard warning lamp operation is the same as that described for the direction indicator lamps operation.