Circuit/System Description

The body control module (BCM) controls the windshield wiper motor based on inputs from the windshield wiper/washer switch, and when intermittent mode is selected, the rain/ambient light sensor module. The BCM monitors the windshield wiper/washer switch through two separate signal circuits and a low reference circuit. The windshield wiper/washer switch utilizes resistive multiplexing to signal a low speed and intermittent operation request to the BCM while a separate discrete signal circuit is used to indicate a high speed wiper request. When the wiper switch is placed in the low speed or intermittent position, the BCM monitors the voltage drop, which changes dependent upon switch position, over an internal pulled high resistor. The BCM will respond by commanding on the low speed or intermittent wipers. With the windshield wiper/washer switch in the high speed position, the BCM's high speed signal circuit is pulled low. The BCM will respond by commanding the windshield wiper motor to operate at high speed via serial data.