Theory Of Operation
WARNING: This page is about a different car, the 2022 Chrysler Voyager and 2022 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.
The Rear Wiper Switch is part of the Multifunction Switch and is integral to the Steering Column Control Module (SCCM). The SCCM sends Rear Wiper Switch commands through the CAN C Bus to the Body Control Module (BCM).
When the BCM receives a message to activate the Rear Wiper, the BCM provides a ground signal, through the Rear Wiper Relay Control circuit, to energize the coil side of the Rear Wiper Relay (integral to the Power Distribution Center (PDC) Assembly). When the Rear Wiper Relay is active, a voltage output is sent through the Rear Wiper Control circuit to the Rear Wiper Motor.
A ground path for the Rear Wiper Motor is provided through the wiring harness to the body of the vehicle.