Wipers and washers (Operation): Description and operation

Operation

General

The wipers and washers operate only while the ignition switch is in position II. Operation of the rear screen wiper and washer is prevented or discontinued if the tail door opens, the tail door window is lowered or, on 3 door models, the roof is opened (soft back) or removed (hard back).

Windscreen Wipers

The wash/wipe stalk, located on the RH side of the steering column, and the CCU control the operation of the wipers. Intermittent wipe, slow speed and fast speed are selected using a rotary wiper control switch on the stalk. A flick wipe function can be selected using the stalk. The CCU is responsible for the operation of the intermittent wipe facility and the park facility when the wipers are turned off.

Intermittent Wipe When intermittent wipe is selected, the wipers operate at slow speed with a delay between wipes. A five position rotary potentiometer, inboard of the wiper control switch, varies the time delay of the intermittent wipe function. The CCU monitors the resistance through the rotary potentiometer and adjusts the time delay to suit the position selected.

The following table details the resistance at each rotary potentiometer position and the corresponding time delays:

Slow and Fast Speeds Slow and fast speed operation is achieved by three brushes in the motor. One brush is the common earth. The slow speed is initiated by a brush positioned 180° to the common brush. The fast speed is initiated by a brush positioned at approximately 45° to the common brush. The fast speed operates by the brushes transferring direct current to a smaller portion of the armature coils, which causes the armature to rotate faster, but with a lower torque than the slow speed.

Flick Wipe The wipers perform a single wipe at fast speed if the wash/wipe stalk is momentarily moved down. If the stalk is held down the wipers operate at fast speed until the stalk is released.

Rear Screen Wiper

The rear screen wiper is controlled from a latching push switch, located on the RH side of the instrument pack cowl, and the CCU. The wiper operates only while the tail door window is closed and, on 3 door models, the roof is closed (soft back) or on (hard back).

The CCU operates the wiper motor via a dual, forward/reverse relay installed above the RH rear suspension turret. The forward relay is energised when the wiper is operating in intermittent and continuous modes. The reverse relay is energised to reverse the rotational direction of the motor to activate the off-screen park function.

Intermittent When the rear window wiper switch is selected on, the CCU initially operates the wiper continuously for approximately 6 seconds (3 or 4 wipes) and then changes to intermittent operation with a fixed delay of five seconds between wipes.