Circuit/System Description

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Ignition voltage is supplied to the windshield outside moisture sensor from the body control module (BCM). Whenever the ignition is in the run or accessory positions, the BCM sends the wiper/washer switch status using a pulse width modulated (PWM) signal through the windshield outside moisture sensor control circuit to the outside moisture sensor. When a wipe cycle is needed, the moisture sensor sends a PWM voltage signal through the moisture sensor signal circuit back to the BCM requesting the wiper operation.

The windshield outside moisture sensor uses the moisture sensor control circuit to command wiper motor wipe cycles and to confirm the moisture sensor signal circuit is being received. If at anytime communication between the windshield outside moisture sensor and BCM is lost, the BCM will use the inputs from the windshield wiper/washer switch in the delay positions to operate the wiper motor at continuous variable delay intervals.