The Wiper/Washer System consists of the following components:

The windshield wiper motor module is part of the windshield wiper motor cover and controls wiper motor operation. Accessory voltage is used to operate the wiper motor and to supply the windshield wiper switch. The windshield wiper switch supplies different voltage levels to the signal circuits. The voltage levels of the windshield wiper switch signal circuits determine the wiper motor operating mode. The windshield wiper motor is a 2 speed motor and is operated at low speed in all modes except HIGH.

When the wiper switch is in the LOW position, voltage is supplied through a 24K ohm resistor within the switch to the signal 2 circuit, and accessory voltage is supplied to the signal 1 circuit. The reduced voltage from the signal 2 circuit and accessory voltage from the signal 1 circuit causes the wiper motor module to close the accessory voltage supply circuit to the wiper motor low speed terminal.

Windshield wiper/washer system MIST operation is identical to 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 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 controlled through a series of resistors within the wiper/washer switch. During DELAY wiper operation the signal 2 circuit is at the same voltage level used for LOW operation, but the signal 1 circuit voltage is reduced through the DELAY resistors. The wiper motor module uses a capacitor feed by the signal 1 circuit to determine the frequency of the low speed wiper motor cycles. When the signal 1 circuit is at the accessory voltage level as in the LOW switch position, the capacitor charges fast causing continuous low speed wiper motor operation. The DELAY switch position indicating the longest interval between wiper motor cycles is the switch position with the highest resistance resulting in low voltage on the wiper switch signal 1 circuit. The low voltage charges the capacitor slowly causing a long delay interval between wiper motor cycles. As the DELAY switch is turned to positions indicating more frequent wiper cycles, the resistance through the wiper/washer switch is reduced and the signal 1 circuit voltage increases. When the signal 1 circuit voltage increases the capacitor charges faster and the delay interval between wiper motor cycles decreases.

When the wiper/washer switch is in the HIGH position the accessory voltage to the wiper/washer switch is closed to the high speed signal circuit. The accessory voltage on the high speed signal circuit causes the wiper motor module to close the wiper motor accessory voltage supply circuit to the wiper motor high speed terminal. During HIGH speed wiper motor operation the wiper switch signal 1 and signal 2 circuits are at the LOW speed signal voltages, but the LOW speed signal circuit inputs to the wiper motor module are overridden by the active HIGH speed signal circuit.

The windshield wiper/washer system WASH function uses 2 switch contacts within the wiper/washer switch assembly. One switch contact closes the wiper/washer switch accessory voltage supply circuit to the wiper switch signal 2 circuit. Accessory voltage on the signal 2 circuit causes the wiper motor module to close the wiper motor accessory voltage supply circuit to the wiper motor low speed terminal. The WASH command on the signal 2 circuit will cause the wiper motor to operate at low speed for as long as the switch is held in the closed position and approximately 6 seconds after being released. The other WASH switch contact in the switch is the control circuit to the windshield washer pump. When the WASH switch is in the held in the closed position the accessory voltage supply circuit is used to operate the windshield washer pump until the switch is released.

Windshield wiper motor park operation is controlled by the wiper motor module using an input from the park switch within the wiper motor assembly. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the module will continue to operate the motor until the wipers reach the park position.

The washer fluid level switch is an input to the body control module which commands the instrument panel cluster to turn the low washer fluid indicator on or off through the class 2 serial data circuit. The washer fluid level signal circuit is supplied ignition voltage through a resistor then monitored within the body control module. The washer fluid level switch is normally open so the body control module detects ignition voltage on the washer fluid level signal circuit whenever the washer fluid level is not low. When the washer fluid level 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 switch signal circuit voltage is pulled low, and the body control module commands the instrument panel cluster to illuminate the low washer fluid indicator. In order to prevent the low washer fluid indicator from flashing due to sloshing in the washer fluid container, the body control module is programed with a 30 second delay before changing states of the low washer fluid indicator during an ignition cycle.