Operation

Wiper Operation

LO (1) and HI (2) positions
The wiper motor has separate brushes and windings for low and high speed operation. When the wiper switch is in LO or HI position, one of the brushes is connected ground through the wiper switch.

OFF position
When the wiper/washer stalk is in OFF and the wipers are not in their park position, the wiper motor remains grounded through its low speed brush, the wiper switch, the timer relay, and the wiper motor switch. The wiper motor will stop running when the wiper motor switch returns to its park position, interrupting the ground connection.

INT position
When the wiper/washer stalk is moved to INT, ground is provided through the wiper switch to the timer. This triggers the timer circuit and momentarily energizes the timer relay. The relay routes ground through the wiper switch to the low speed brush long enough for the motor to pull the wipers out of the park position. The wiper motor stops when the wipers return to their park position. when the timer circuit times out, it again energizes the relay momentarily, repeating the wiper cycle, the timer circuit's time period can be varied by rotating the wiper stalk, on vehicles so equipped.

One Touch Wipers
When the wiper stalk is pushed momentarily away from the driver, the wiper motor's low speed brush is grounded through the one touch switch long enough for the wiper to move away from its PARK position. Once moved, it will continue to sweep because the wiper motor's low speed brush is now grounded through the wiper motor switch, the timing circuit, and the wiper switch. After one cycle, when the wiper returns to its PARK position, ground will be removed from the low speed brush and wiper operation will cease. Also, the wipers will continue to operate for as long as the wiper stalk is held in the one-touch position.

Washer operation
When the wiper/washer stalk is pulled towards the driver, ground is provided through the washer switch to the washer motor, powering it. This motor drives a pump that sprays fluid on the windshield. The washer switch also provides ground to the timer relay, which in turn powers the wiper motor. The timer relay will continue to power the wiper motor until the washer switch is released.