Wiper and Washer Systems: Description and Operation

OPERATION
The windshield wipers can be operated with the windshield wiper switch only when the ignition switch is in the Accessory or Ignition position. A fuse located in the fuse block protects the circuitry of the wiper system. The same motor is used for standard and intermittent wipe systems.

The wiper motor has a permanent magnetic field. Speed is controlled by current flow to the appropriate set of brushes.

The intermittent wipe system, in addition to high and low speed, has a delay mode. The delay mode has a range of 2 to 15 seconds. This is accomplished by a variable resister in the wiper switch and is controlled electrically by a relay.

The wiper system completes the wipe cycle when the switch is turned Off. The blades park in the lowest portion of the wipe pattern.

CIRCUIT OPERATION
Fuse 8 in the fuse block powers the intermittent wiper system. The intermittent wiper system operates at either DELAY, LOW or HIGH speeds.

In the ACCESSORY or RUN position, the ignition switch connects circuit A1 from fuse 3, a 40 amp, in the Power Distribution Center (PDC) with circuit A31. Circuit A31 supplies voltage to circuit V6 through fuse 10 in the fuse block.

Circuit V6 splices to supply power to the wiper switch circuitry in the multi-function switch, the intermittent wiper module and the park switch in the wiper motor. Ground for the wiper motor is supplied on circuit Z1. Circuit Z3 provides ground for the intermittent wiper control module.

When the operator moves the wiper switch to the LOW speed position, the switch passes voltage to circuit V3. Circuit V3 feeds the wiper motor LOW speed brushes. If the operator selects wiper HIGH speed operation, the wiper switch passes current to circuit V4. Circuit V4 feeds the wiper motor HIGH speed brushes.

If the operator selects wiper DELAY operation, the wiper switch provides an input to the intermittent wiper control module on circuit V9. The DELAY portion of the wiper switch contains a variable resistor. The variable resistor connects to the intermittent wiper module on circuit V9. Voltage for the resistor is supplied by circuit V6 through the wiper switch. The amount of delay selected by the operator determines the voltage drop through the resistor and the voltage level received by the intermittent wiper module.

After the intermittent wiper control module determines the amount of delay selected, it cycles the wipers by periodically energizing circuit V17 which connects to circuit V3 through the wiper switch. Circuit V3 powers the wiper motor LOW speed brushes.

As the windshield wiper motor turns, the park switch, internal to the motor, moves from its grounded position (down) to the powered RUN (up) position. Circuit V7 provides an input to the intermittent wiper control module when the wiper switch is in the OFF position. The intermittent wiper control module powers the park switch in the wiper motor on circuit V5.

The intermittent windshield wiper system is also equipped with a pulse wipe feature. To activate this feature, the operator presses the washer switch momentarily. When the washer switch closes, voltage from circuit V6 passes through the switch to circuit V10. Circuit V10 provides a signal to the intermittent wiper control module and supplies voltage for the windshield washer pump. When the control module receives the signal on circuit V10, it cycles the wipers on circuit V3 while the washer fluid pump operates.

The washer motor operates whenever the washer switch CLOSES and supplies voltage to it on circuit V1O. Circuit Z1 provides ground for the pump motor.