Windshield Wiper/Washer System Operation

The outside moisture sensor controls wiper motor operation for all low speed modes. The high speed mode maybe controlled by the both windshield wiper/washer switch and the outside moisture sensor. The windshield wiper motor is a 2 speed motor and is operated at low speed in all modes except HIGH. The accessory voltage supply circuit to the outside moisture sensor provides the power for controlling the wiper motor. The MIST, LOW, and DELAY modes are controlled by the windshield wiper/washer switch through a series of internal resistors, and the switch position determines the point on the resistor assembly where the reference voltage is applied. For these modes, the windshield wiper switch signal circuit supplies the signal from the switch assembly to the outside moisture sensor which determines the operating mode. Windshield wiper motor high speed operation is controlled by the windshield wiper/washer switch and the outside moisture sensor through the windshield wiper switch high speed signal circuit. The low speed modes energize the wiper ON/OFF relay and the voltage is supplied through the wiper HI/LO relay to the windshield wiper motor. At HIGH position the wiper HI/LO is energized and supplies voltage to the high speed circuit of the windshield wiper motor.

The windshield washer fluid pump is controlled by the windshield wiper/washer switch through the windshield washer fluid pump relay. The windshield washer fluid pump relay coil and switch are supplied battery positive voltage, and during the windshield window wash modes the windshield wiper/washer switch grounds the washer fluid pump relay control circuit energizing the relay. During the windshield washer operation the switch signals the outside moisture sensor also, to provide low speed wipers operation.

The outside moisture sensor provides automatic operation for low and high speed when the windshield wiper/washer switch is in DELAY position. The outside moisture sensor is an electronic module that uses infrared radiation to determine the level of windshield visibility for the driver, and commands the wiper motor/controller assembly to drive the wipers to maintain a pre-selected level of visibility.