Rear Wiper/Washer System

Rear Wiper/Washer System Description and Operation

The rear wipe/wash function is controlled by the use of a rear wiper motor with an integrated electronic control module.

Both the front and rear wash operations are accomplished by the use of a single reversing washer fluid pump motor. In this system the wash motor is operated in one direction to spray fluid on the front windshield and then operated in the reverse direction to spray fluid on the rear window. Thus there is a relay connected to each input of the washer pump motor.

The rear wiper/washer signal is received by the rear wiper motor/module and is the result of three resistors in the rear wiper switch configured as a resistor ladder network. This signal is connected to a digital input which also provides a switched battery pull-up for the circuit. Depending on the function selected (Intermittent 1, Intermittent 2, Off, Wash), the rear wiper control switch connects a different set of resistors into the circuit resulting in different voltages appearing on the rear wiper motor/module input. By monitoring this voltage, the BCM determines how to control the rear wiper motor and the rear washer relay.