Reverse Gear Wiper Function (page 2 of 2)

When reverse gear is disengaged or the front windscreen wipers are switched off, the earth path to the CCU is removed. This removes the supply to the rear wiper relay forward relay coil. The rear wiper will complete its cycle until the CCU senses a signal, from a switch within the motor, that it is at the off screen position. A feed from fuse 8 in the passenger compartment fusebox passes through the CCU (C429-4) to the rear wiper relay (C124-1) on a yellow and white wire. This energizes the coil of the reverse relay which provides an earth from the rear screen wiper motor (C388-2) on a green wire to the rear wiper relay (C124-6). The earth path is completed from the relay (C124-4) to an earth header joint (C551-1) on a black wire. Simultaneously, a feed is supplied from fuse 30 of the passenger compartment fusebox (C583-4) to the rear wiper relay (C124-2) on a purple and red wire. The feed passes through the contacts of the forward relay and is connected from the rear wiper relay (C124-9) to the rear screen wiper motor (C388-1) by a green and red wire.

The rear screen wiper motor operates in the reverse direction. An offset cam in the wiper motor rotates through 180 degrees and allows the rear screen wiper motor to move the wiper arm to a lower position than its operating position. This parks the wiper off screen. Switches within the motor signal the CCU when the wiper is in its park position. The CCU then removes the feed to the rear wiper relay reverse coil. This, in turn, removes the earth path for the rear screen wiper motor which stops operating, leaving the wiper off screen in the park position.

When reverse gear is disengaged or the front windscreen wipers are switched off, the signal to the CCU is terminated. The removal of the signal input to the CCU disconnects, after a predetermined delay, the feed through the CCU from fuse 8 of the passenger compartment fusebox to the rear wiper relay.