Wiper/Washer System Operation

The windshield wiper motor module is pan of the windshield wiper motor cover and controls wiper motor operation during all operating modes except HIGH. The operating voltage to the windshield wiper motor assembly is supplied through the windshield wiper/washer switch. The accessory voltage supply circuit to the windshield wiper/washer switch is controlled by the accessory relay in the underhood fuse block.

During windshield wiper/washer system LOW operation, accessory voltage is supplied to the windshield wiper motor module through the wiper switch signal 2 circuit and the washer switch signal circuit. The wiper switch signal 2 circuit is used to supply the operating voltage to the wiper motor assembly during all low speed wiper motor operating modes. The primary function of the windshield washer switch signal circuit is to supply the operating voltage to the wiper motor assembly used to return the wiper motor to the park position after the wiper switch is turned to the OFF position.

Windshield wiper/washer system MIST operation is identical to LOW operation except that the MIST switch is a press and release type. 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 windshield wiper motor will operate in the LOW mode until the switch is released.

When the wiper/washer switch is in the HIGH position the accessory voltage to the wiper/washer switch is closed to the wiper motor high speed circuit. The wiper motor high speed circuit is supplied directly to the windshield wiper motor high speed terminal and supplies the operating voltage to the wiper motor during high speed operation.

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 wiper switch signal 2 circuit is at the same voltage level used for LOW operation, but the windshield washer switch signal circuit voltage is reduced through the DELAY resistors. The windshield wiper motor module uses a capacitor feed by the windshield washer switch signal circuit to determine the frequency of the low speed wiper motor cycles. When the windshield washer switch signal 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 windshield washer switch signal 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 windshield washer switch signal circuit voltage increases. When the windshield washer switch signal circuit voltage increases the capacitor charges faster and the delay interval between wiper motor cycles decreases.

During windshield wiper/washer system WASH operation the wiper switch signal circuit inputs to the wiper motor module are identical to the LOW or MIST inputs. The windshield washer switch signal circuit wash command to the wiper motor module is used to activate windshield washer pump operation.

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 windshield wiper/washer switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the wiper motor module will continue to operate the wiper motor until the wipers reach the park position.

"For a description of the RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at Vehicle/Application ID". RPO Codes