The Wiper/Washer System consists of the following components:

Refer to Master Electrical Component List.

With the ignition in the ON position, accessory voltage is supplied through the 25A WPR fuse to the WIPER PCB relay, the WIPER HIGH PCB relay and the WS WASH PCB relay that are all located in the underhood fuse block. Refer to Wiper/Washer Schematics.

G200 provides ground for the windshield wiper motor and the WIPER PCB relay. G100 provides ground for the windshield washer fluid pump and the windshield washer fluid level switch.

When the wiper switch is in the low speed position, ground is applied through the switch internal resistor and the wiper switch low signal circuit to the body control module (BCM). In response to this signal, the BCM energizes the WIPER PCB relay by applying battery voltage through the wiper relay control circuit to the coil side of the relay. This allows battery positive voltage from the WPR fuse to flow through the switch input side of the WIPER PCB relay and out to the switch input side of the WIPER HIGH PCB relay. Since the wiper high relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the windshield wiper motor, the motor will operate at low speed.

Wiper motor low speed operation and the wiper PCB relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References.

Windshield wiper/washer system MIST operation is identical to wiper Low operation, except that the mist switch is a press and release type switch. When the wiper switch is moved to the mist position and released, low speed wiper motor operation is started and will continue until 1 wipe cycle is complete. If the wiper switch is moved to the mist position and held, the wiper motor will operate in the low mode until the switch is released.

Windshield wiper delay operation is a low speed wiper motor function with a variable delay interval between the wiper motor cycles. The delay interval is determined by a series of 6 resistors within the wiper/washer switch. The body control module (BCM) monitors the wiper switch low signal circuit to determine the delay interval between the low speed wiper motor wipe cycles.

When the wiper switch is in the high speed position, ground is applied through the windshield wiper switch high signal circuit to the body control module (BCM) indicating the wiper high speed request. In response to this signal, the BCM then energizes the wiper PCB relay, as stated above, and the wiper high PCB relay by applying ground through the control circuit to the coil side of the relay. With the wiper high relay energized and its switch contacts closed to the high speed control circuit of the wiper motor, the motor will operate at high speed.

Wiper motor high speed operation and the wiper high speed PCB relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References.

When the windshield Wash switch is pressed, ground is applied through the switch contacts and the windshield washer switch signal circuit to the body control module (BCM) indicating the windshield wash request. The BCM then energizes the wiper PCB relay, as stated above, and the WS WASH PCB relay by applying ground through the control circuit to the coil side of the relay. With the wash relay energized, battery voltage from the WPR fuse is applied through the switch side of the relay and out to the control circuit of the windshield washer fluid pump. The washer fluid pump and the wiper motor will operate for 2 wipe cycles after the wash switch is released.

The WS WASH PCB relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References.

Windshield wiper motor park operation is controlled by the body control module (BCM) using an input from the park switch that is located within the wiper motor assembly. The BCM monitors the windshield wiper motor park switch signal circuit, to determine if the windshield wiper blades are at the bottom of the glass. During wiper operation, each time the wiper blades are at the bottom of the glass, the park switch is momentarily closed to ground signaling the BCM the wiper position. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will continue to operate the motor until the wipers reach the park position. If the ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately where they are. The BCM will park the wipers the next time the ignition is turned ON.