Operation

Wipers and Washers

OPERATION

Front

General
Feed from the positive battery terminal (C0192) is supplied to fusible link 3 of the engine compartment fuse box (C0632) on an P wire. Fusible link 3 (C0571) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 8 (C0588) on a G wire, and fuse 3 (C0588) on an NW wire. Both are located in the passenger compartment fuse box.

Fuse 8 and fuse 3 (C0593) both provide an ignition feed to the front wiper relay contained within the Central Control Unit (CCU). The CCU (C0593) is earthed via the passenger compartment fuse box (C0587) on a B wire.

Intermittent Wipe
Fuse 3 of the passenger compartment fuse box (C0580) provides an ignition feed to the wiper switch (C0035) on an LG wire, and the variable wipe potentiometer (C0320) on a GY wire. When the wiper switch is moved to the intermittent wipe position, current flows across the switch (C0035) to the CCU (C0428) on a G wire.

The variable wipe potentiometer has 5 pre-set positions. The potentiometer (C0320) is connected to the CCU (C0429) by a WK wire. The voltage supplied to the CCU by the potentiometer is dependent upon its position. The CCU is able to determine the amount of delay to apply to the wipers by measuring the voltage provided on the WK wire.

When the CCU receives a feed from the intermittent wipe switch and the potentiometer, it provides an intermittent feed back to the wiper switch (C0035) on a LGK wire. The wiper switch (C0035) is connected to the wiper motor (C0030) by a ULG wire. Current flows across the motor slow speed windings and is earthed (C0030) on a B wire.

Slow Wipe
Fuse 3 of the passenger compartment fuse box (C0580) provides an ignition feed to the wiper switch (C0035) on a G wire. When the wiper switch is moved to the slow wipe position, current flows across the switch (C0035) to the wiper motor (C0040) on a ULG wire. Current flows across the motor slow speed windings and is earthed (C0030) on a B wire.

Fast Wipe
Fuse 3 of the passenger compartment fuse box (C0580) provides an ignition feed to the wiper switch (C0035) on a G wire. When the wiper switch is moved to the fast wipe position, current flows across the switch (C0035) to the wiper motor (C0030) on a RG wire. Current flows across the motor fast speed windings and is earthed (C0030) on a B wire.

Park
Fuse 3 of the passenger compartment fuse box (C0582) provides an ignition feed to the wiper motor park switch (C0030) on an LG wire. The park switch is closed with the wipers in any position other then the park position.

When the wipers are turned off, current flows across the park switch (C0030) to the CCU (C0430) on an NLG wire. The CCU (C0430) is connected to the wiper switch (C0035) by an LGK wire. The wiper switch (C0035) provides a feed to the wiper motor (C0040) on a ULG wire. Current flows across the motor slow speed windings and is earthed (C0030) on a B wire. When the wipers reach the park position, the switch contacts open and power to the wiper motor is cut.

Washers
Fuse 3 of the passenger compartment fuse box (C0580) provides an ignition feed to the washer switch (C0035) on an LG wire. When the RH column stalk is pulled back against spring pressure, current flows across the switch (C0035) to the washer pump (C0008) on a LGB wire. The washer pump (C0008) is earthed on a B wire.

The washer switch (C0035) also provides a feed to the CCU (C0428) on an LGB wire. When the CCU receives this feed, it initiates its programmed wash/wipe function.

Rear

General
Feed from the positive battery terminal (C0192) is provided to fusible link 3, and fusible link 4 of the engine compartment fuse box (C0632) on an R wire. Fusible link 4 (C0574) is connected to fuse 30 and fuse 14 of the passenger compartment fuse box (C0587) by an NW wire. Fuse 30 (C0583) provides a constant battery feed to the rear wiper relay (C0124) on a PR wire. Fuse 14 (C0583) provides a constant battery feed to the 'Roof On' switch (C0497) on a P wire.

Fusible link 3 (C0571) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 1 of the passenger compartment fuse box (C0588) on an NW wire. The ignition switch (C0028) also provides a feed to fuse 8 of the passenger compartment fuse box (C0588) on a G wire.

Wiper
The CCU (C0592) monitors the condition of the wiper switch (C0079) by providing a feed via the passenger compartment fuse box (C0589) on an RG wire. When the switch is pressed, current flows across the switch contacts (C0079) to earth on a B wire. When the CCU registers this earth, it provides a feed to the rear wiper relay (C0124) on a YB wire. The rear wiper relay contains two independent relays; a forward relay and a reverse relay.

The energized forward relay (C0124) is now able to provide a feed to the wiper motor (C0388) on a GR wire. Current flows across the motor windings (C0388) and back to the rear wiper relay (C0124) on a G wire.

To move the wiper back, the CCU (C0429) removes the feed to the wiper relay on a YB wire and provides a feed on a YW wire. This feed energizes the reverse relay, which is earthed on a B wire.

The energized reverse relay (C0124) is now able to provide a feed to the wiper motor (C0388) on a G wire. Current flows across the motor windings (C0388) and back to the rear wiper relay (C0124) on a GR wire.

Off-Screen Park
The CCU (C0428) monitors the off-screen park function of the rear wiper (C0388) by providing a signal feed on OB and NG wires.

Tail Door Window Lift
The rear wiper will not operate if the tail door glass is not in the fully closed position. If the tail door window is open. The CCU (C0428) monitors the condition of the tail door window via the tail door window switch (C0354) on BR and BK wires. The switch (C0354) is earthed on a B wire.

Washer
Fuse 1 of the passenger compartment fuse box (C0589) provides an ignition feed to the washer switch (C0073) on a GY wire. When the switch is depressed, current flows across the switch contacts (C0073) to the washer pump relay (C0936) and the CCU (C0428) on GB wires.

When the CCU receives this feed, it initiates its programmed wash/wipe function, and provides a feed to the rear wiper relay (C0124) on a YB wire. The rear wiper relay operates the rear wiper as described above.

The rear wiper relay (C0124) also provides a feed to the washer pump relay (C0936) on a GR wire. This energizes the washer pump relay, which is earthed on a B wire. The energized washer pump relay (C0936) provides a feed to the washer pump (C0021) on a GB wire. The pump (C0021) is earthed on a B wire.

Tail Door Switch
The CCU (C0428) monitors the condition of the tail door switch (C0616) by providing a feed on a BO wire. The tail door switch is open circuit when the tail door is closed. When the tail door is opened, the switch contacts close and an earth path is created on a B wire. Sensing this earth path, the CCU suspends operation of the rear wiper.

Roof On Switch (3 Door Vehicles Only)
Fuse 14 of the passenger compartment fuse box (C0583) provides a constant battery feed to the roof on switch (C0497) on a P wire. The roof on switch is closed when the hard back is fitted, or the soft back is in the fitted position. In this instance, current flows across the switch (C0497) to the CCU (C0428) on a PY wire.

If the hard back is removed (or the soft back is folded down) the roof on switch becomes open circuit, and the feed to the CCU is removed. When the CCU registers this, it suspends operation of the rear wiper.