Programmed Wash/Wipe

Programmed Wash/Wipe

Washer fluid is sprayed onto the windscreen from the bonnet mounted jets, when the right-hand steering column lever is pulled towards the driver. Operation of this switch provides a supply via a B/G wire, to the windscreen washer pump. The earth path is on a B wire.

Operation of this switch also sends a voltage to the MFU on the B/G wire. The MFU causes the wiper motor to run 0.6 second after the washer switch is operated, for as long as the switch remains operated and for a period of 2 seconds after the switch is released. This latter period is sufficient for two complete sweeps of the windscreen wiper blades.

Rear Screen

The MFU controlled, single speed rear screen wiper and wash functions, will not operate unless the ignition switch is turned to position ’II’. A 4-position switch, mounted inboard of the front windscreen wiper and washer switches, is used to select wipe and wash functions; positions 1 and 4 of the switch are spring-loaded.

Wiper Operation

When the ignition switch is turned to position ’II’, battery voltage is supplied to the rear wash wipe switch on two G/B wires via fuse 14 of the passenger compartment fuse box. Fuse 14 also supplies a feed to the rear wiper relay coil and the rear wiper motor. Both of these are connected by G/B wires.

An earth path for the rear wiper relay coil is on a B/G wire and is controlled by the MFU. When the MFU receives a voltage signal from the rear wash wiper switch, it energises the rear wiper relay. The relay now provides an earth path for the motor on a LG/B wire.

Under the influence of the MFU, the wiper operates continuously for 6 seconds, then intermittently - once every 6 seconds - until the wiper switch is turned to OFF (position 2).