Wiper and Washer Systems: Description and Operation

The windshield wiper motor operates at slow or fast speed, and drives, via a rack assembly, a single arm and blade. The wiper is supplemented by washers, which spray jets of fluid into the path of the wiper blade as it moves across the windshield. Intermittent/Mist wiper operation is at slow speed and controlled by the ECU. The ECU also controls headlamp washer operation.
The windshield wiper and washer switch operates when ignition is ``On'' and has the following positions:
1. Wiper switched Off and parked. Normal speed operation of wiper, obtained by pushing switch lever up one position.
2. High speed operation of wiper, obtained by pushing lever fully up.
3. Intermittent operation, obtained by pushing switch lever down against spring pressure and releasing. To cancel function, push switch down again and release.
To obtain a single sweep (flick), pull lever towards steering wheel and release. To operate washers, press end of switch lever.
When the wiper switch is in either the slow or fast position, a circuit to ground is completed for slow or fast speed relays located in a wiper logic module. When ignition switch is On, the appropriate relay is energized and battery power is applied to fast or slow speed windings of the wiper motor.
For intermittent wiper operation, a logic ground is applied to connector B13-4 of the ECU, which responds by energizing the slow speed relay for periods of half a second at five second intervals. Wiper operation in intermittent mode continues until cancelled by either a second application of the switch or by selecting another mode.
For mist operation, a logic ground is applied to connector B12-5 of the ECU, which responds by energizing the slow speed relay. The relay is energized for a single period of half a second and wiper motor control is undertaken by a self parking mechanism which causes the wiper arm to complete one sweep of the windshield and then park.
The self parking mechanism is installed in the wiper motor assembly and consists of brushes that engage inner and outer slip rings. The slip rings are arranged so the outer supplies battery power to the slow speed circuit until park position is reached and inner supplies a ground to the motor circuit at the park position to provide dynamic braking. These inputs are applied to the slow speed circuit through the logic module connector No. B59-9, battery power is supplied to the outer slip ring through connector No. B59-6.