Windshield Wiper/Washer System Components
The windshield wiper/washer system consists of the following components:
• | Windshield wiper/washer switch |
• | Windshield washer relay |
Windshield Wiper/Washer System Operation
Accessory voltage and ground are supplied to the windshield wiper motor. Accessory
voltage provides the power for operating the wiper motor and wiper motor module logic.
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 are 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 during windshield wiper motor operation.
Check Washer Fluid Message
The Check Washer Fluid message is controlled by the instrument panel cluster (IPC)
using a discrete 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 when slosh occurrs 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.