Wiper and Washer Systems: Description and Operation

CIRCUIT OPERATION

In addition to the features of a conventional (non-pulse) wiper system (low and high speed), the pulse-type Windshield Wiper/Washer System includes an operating mode in which the Wipers make single strokes with an adjustable time interval between strokes. The time interval is controlled by a Solid State Timer in the Wiper Motor Module. The duration of the delay interval is determined by the delay rheostat in the Wiper Washer Switch.

The Wiper Motor is protected by a circuit breaker. If the Wipers are blocked (by snow or ice for example) the Circuit Breaker will open the circuit. The Circuit Breaker resets automatically when it cools.


Pulse Operation

With the Wiper/Washer Switch in PULSE, battery voltage is applied to the Wiper Motor Module at terminal B of connector C1 through the GRY wire. Voltage is also applied to terminal F through the PNK wire and the pulse delay resistor in the Wiper Washer Switch. The battery voltage at terminal B energizes the Park Switch Coil which closes its contacts. In response to the voltage at terminal F, the Solid State Timer momentarily closes contact A on the Cover Assembly which applies battery voltage at terminal B to the contacts of the Park Switch, starting the Wiper Motor.

A mechanical arm (end of sweep input) operates contacts on the Cover Assembly, which cause contact A to open when the Wipers have completed their sweep. Since the Park Switch Coil remains energized, the Wipers do not park but remain just above the park position until the Cover Assembly closes contact A again to start another sweep.

The length of delay time between sweeps is controlled by the variable Pulse Delay resistor. The delay is adjustable from 0 to 25 seconds.

Low Speed

With the Wiper Switch in LO, battery voltage is applied at the Wiper Motor Assembly connector C1, terminals B and C through the DK GRN and GRY wires. The Park Switch Coil is again energized and battery voltage is applied to the Park Switch contacts and the Wiper Motor, which runs continuously.

High Speed

With the Wiper Switch in the HI position, battery voltage is applied directly to the Wiper Motor, at terminal A, without passing through the Park Switch contacts. Terminal A is connected to a separate Wiper Motor brush for high speed operation. The Park Switch coil remains energized in the HI position because of the voltage that is present at the low speed Wiper Motor brush when voltage is applied to the high speed brush. The current path from the low speed brush to the Park Switch coil is completed through the Wiper/Washer Switch. An open in the this circuit will cause the wipers to be inoperative in LO, and cycle in and out of park in HI


Washer

When the Washer Switch is held ON, battery voltage is applied to the Cover Assembly through the PNK and GRY wires. The Park Switch Coil is energized by the battery voltage at terminal B of connector C1. The Cover Assembly turns on the Washer and Wiper Motors by closing contacts A and B. The Cover Assembly turns the Wiper Motor off approximately six seconds after it interrupts power to the Washer Motor. If the Wipers had been in PULSE, LO or HI, they would return to that operation after the wash cycle.