Circuit/System Description

The body control module (BCM) controls the windshield 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 low reference 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 the windshield washer switch signal circuit is used to determine wiper/washer operation.

The BCM controls the windshield wiper motor low, high, intermittent, and park operations through a serial data circuit. If serial data communication is interrupted, a control circuit is used as a backup to ensure that wiper functionality is not lost. B+ is applied to the control circuit and will allow limited wiper operation when the windshield wiper/washer switch is in the HIGH position.