Circuit/System Description

The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation. The windshield wiper motor park operation is controlled by the BCM. The BCM receives an input from the park switch to determine wiper blade position. When the wiper blades are at the bottom of the windshield glass in park position the wiper park switch will open and the circuit will be pulled up to B+ by the BCM. The park signal will be pulled to ground by the wiper motor park switch while the wiper blades are not in the park position.

The BCM controls the windshield wiper motor through 2 output controls, controlling 2 relays which determine the desired wiper speed, high or low.