Wiper/Washer System Operation

The windshield wiper motor module is part 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. The jumper circuit from the wiper motor module to the wiper motor high speed circuit enables the wiper motor module to operate the wiper motor at high speed during moisture sensitive wiper system operation.

The moisture sensitive operating mode is activated whenever the windshield wiper/washer switch is to one of the 5 AUTO DELAY switch positions. The wiper/washer switch contains a series of resistors which are used to vary the voltage level of the windshield washer switch signal circuit. The windshield washer switch signal circuit is an input to the outside moisture sensor and determines the sensitivity level of the moisture sensitive wipers. When the moisture sensor detects sufficient moisture accumulation on the windshield or the AUTO DELAY switch position is advanced, a wipe command is sent to the wiper motor module through the moisture sensor low signal circuit. The moisture sensor high signal circuit is used to command high speed wiper motor operation when low speed operation is unable to sufficiently clear moisture accumulation.

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 to the moisture sensor relays a wash command to the wiper motor module 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