Electrical (Windscreen wipers): Description and operation

WINDSCREEN WIPERS

The CCU is programmed to control the windscreen wipers intermittent wipe and programmed wash/wipe facilities. The windscreen wipers are operated from the right hand stalk switch on the steering column.

Intermittent Wipe

A five position rotary potentiometer, inboard of the wiper control switch, operates the intermittent wipe delay function. The five positions operate the wipers intermittently at time delays of approximately 3, 5, 8, 12 and 17 seconds. The CCU monitors the resistance through the intermittent switch and adjusts the delay to suit the position selected.

The following table details the wiper switch position and corresponding switch resistance and time delay:

The CCU windscreen wiper inputs and outputs are shown in the following table:

Programmed Wash/Wipe

The programmed wash/wipe is operated by pushing the right hand stalk on the steering column downwards. The length of time that the wash/wipe function operates is determined by the time that the switch is operated.

When the switch is operated, the washers operate immediately. The CCU suspends wiper operation for approximately 0.6 seconds before energising the wiper relay coil, allowing the wipers to operate.

When the switch is released the washers immediately stop. The CCU continues to energise the wiper relay coil for a further 2 seconds after the switch is released, which allows the wipers to wipe the screen after the washers have stopped.