Rain Sense Mode and Rain Sense Indicator

B+ voltage is supplied to the rain sensor. Whenever the ignition switch is in the on, or accessory positions, the body control module (BCM), sends the windshield wiper/washer switch status by using serial data. When a wipe cycle is needed, the rain sensor sends a data communication message to the BCM, requesting the wiper operation. The BCM commands the Windshield Wiper Motor wipe cycles. If at anytime a fault occurs between the rain sensor and BCM, the BCM will use the inputs from the windshield wiper/washer switch in the delay positions to operate the windshield wiper motor at continuous variable delay intervals.

Fig 1: Rain Sensor Block Diagram

Courtesy of GENERAL MOTORS COMPANY