Headlamp Wash/Wipe

HEADLAMP WASH/WIPE

DESCRIPTION

General
Operation of the headlamp wash/wipe system is controlled by the Body Control Unit (BCU) via the headlamp wash/wipe relay. Headlamp wash/wipe is activated automatically when the ignition and the headlamps are switched on, and windscreen wash/wipe is selected via the column switch. The headlamp wipers will operate through four cycles, with the washer jets spraying Mice. This operation is only carried out on the first windscreen wash/wipe request, and then every fifth request from then on. This sequence is reset when the ignition is switched off.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 28 and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 28 (C0582) provides a constant battery feed to the following on RS wires:
- The headlamp wash/wipe relay (C2031)
- The RH headlamp wiper motor (C3341)
- The LH headlamp wiper motor (C1340).

Fuse 53 (C0583) provides a constant battery feed to the ignition switch (C0028 on V8 vehicles) on an R wire. When the ignition switch is turned to the 'auxiliary' position, current flows across the switch (C0028 on V8 vehicles) to fuse 41 of the passenger compartment fuse box (C0585) on a PB wire. Fuse 41 (C0586) provides an auxiliary ignition feed to the BCU (C0660) on a PW wire. The BCU (C0662) is earthed on an N wire.

Headlamp Wash/Wipe Relay
When the BCU (C0661) determines a wash/wipe selection has been made, it provides a pulsed voltage feed to the headlamp wash/wipe relay (C2031) on a UB wire. The headlamp wash/wipe relay (C2031) is earthed on an NB wire. When this feed is received, circuitry contained within the relay converts this signal into a headlamp wash/wipe request and closes the relay switch contacts. This allows a feed to be provided to the RH headlamp motor (C1341) and the LH headlamp motor (C1340) on a pair of BN wires. Current flows across the motors to earth on N wires.