The windshield wiper/washer system consists of the following components:

Accessory voltage and ground is supplied to the windshield wiper motor and provides the power for operating the wiper motor and logic power to the wiper motor module. The WASH, MIST, LOW, and DELAY modes are controlled by the windshield wiper/washer switch through a series of internal resistors. The windshield wiper switch supply voltage circuit is a 12-volt reference from the wiper motor module to the wiper/washer switch, and the switch position determines the point on the resistor assembly where the reference voltage is applied. The windshield wiper switch signal 1 circuit supplies the voltage from the resistor assembly to the wiper motor module and the signal voltage determines the operating mode. High speed operation is controlled by the windshield wiper/washer switch through the windshield wiper switch high signal circuit. The windshield wiper switch high signal circuit is supplied 12 volts by the wiper motor module and when the wiper/washer switch is turned to the HIGH position the windshield wiper switch high signal circuit is grounded through the switch ground circuit. The windshield washer pump is controlled through the windshield wash relay. The windshield wash relay coil and switch is supplied battery positive voltage, and during WASH mode the wiper motor module grounds the washer relay control circuit energizing the relay. When the relay is energized battery positive voltage to the switch side of the relay is supplied to the washer pump control circuit. The windshield wiper switch signal 2 circuit from the wiper motor module is used by the body control module as a signal to turn on the low beam headlamps.

The outside moisture sensor monitors moisture accumulation on the windshield and provides an input to the windshield wiper motor module. If no moisture is detected, the wipers will not operate in the DELAY modes. The windshield wiper switch signal 1 circuit is used to activate the automatic operating mode and to adjust the level of sensitivity to moisture accumulation when commanding a wiper motor wipe cycle. The moisture sensor sends a PWM voltage signal to the wiper motor module through the moisture sensor signal 1 circuit whenever the ignition is in the accessory or run positions. If at anytime the moisture sensor signal 1 circuit PWM voltage signal input to the wiper motor module is lost, the wiper motor module will use the input from the windshield wiper switch signal 1 circuit to operate the wiper motor at continuous variable delay intervals.

The Check Washer Fluid message is controlled by the instrument panel cluster using an input from the washer fluid level switch. The washer fluid level signal circuit is supplied ignition voltage through a resistor then monitored within the instrument cluster. The washer fluid level switch is normally open so the instrument cluster detects ignition voltage on the washer fluid level signal circuit whenever the washer fluid level is not low. When the washer fluid reaches the point where the driver should be informed that the washer fluid is low, the washer fluid level switch closes. When the washer fluid level switch is closed the washer fluid level signal circuit voltage is pulled low, and the instrument panel displays the Check Washer Fluid message on the driver information center. In order to prevent the Check Washer Fluid message from being displayed while sloshing is occurring in the washer fluid container, the instrument cluster is programed with a 1 minute delay before changing states of the Check Washer Fluid message during an ignition cycle.