Circuit/System Description
WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
B+ voltage is supplied to the windshield outside moisture sensor. Whenever the ignition is ON, or in accessory positions, the body control module (BCM), sends the wiper/washer switch status by using a pulse width modulated (PWM) signal. When a wipe cycle is needed, the windshield outside moisture sensor sends a PWM voltage signal to the BCM, initiating the wiper operation. The BCM commands the windshield wiper motor wipe cycles. If a fault occurs at any time between the windshield outside moisture sensor and BCM, the BCM will use the inputs from the turn signal/multifunction switch in the delay positions to operate the windshield wiper motor at continuous variable delay intervals.