Wiper and Washer Systems: Description and Operation

How the Circuit Works

Low Speed
With the ignition switch in ON (II) or START (III), battery voltage is applied to the windshield wiper motor through fuse 20 (in the under-dash fuse/relay box). When the wiper switch is moved to LOW, the low speed windings of the windshield wiper motor are grounded through the low contact of the wiper/washer switch to G401. Grounding the low speed windings causes the wipers to run at low speed.

Park/Off
When the wiper switch is in OFF, ground is provided for the low speed windings of the windshield wiper motor through the cam switch on the motor to G301. The wipers then run at low speed until the cam switch on the motor moves to PARK, removing the ground which stops the wipers in the park position.

High Speed
When the wiper switch is moved to HIGH, the high speed windings of the windshield wiper motor are grounded through the high contact of the wiper/washer switch to G401. Grounding the high speed windings causes the wipers to run at high speed.

Intermittent
When the wiper switch is moved to INT, battery voltage is applied through fuse 20 (in the under-dash fuse/relay box) to the multiplex control unit. The multiplex control unit provides a ground through the wiper/washer switch to the low speed windings of the windshield wiper motor. The wipers make a single sweep every few seconds.

Mist
When the wiper/washer switch lever is pushed down, the high speed windings of the windshield wiper motor are grounded through the mist contact of the wiper/washer switch to G401. The wipers sweep at high speed until the wiper/washer switch lever is released. The PARK/OFF function then takes over and the wipers stop in the PARK position.

Washer
When the wiper/washer switch lever is pulled toward the driver, battery voltage is applied to the windshield washer motor and the multiplex control unit through fuse 20 (in the under-dash fuse/relay box). The multiplex control unit applies ground to the low speed windings of the windshield wiper motor. The windshield washer motor then pumps washer fluid onto the windshield while the wipers run at low speed. When the wiper/washer switch lever is released, the wipers make one more sweep and then stop.