Theory Of Operation

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The Front Wiper Switch is part of the Multi-function Switch and is integral to the Steering Column Control Module (SCCM). The SCCM sends Front Wiper Switch commands through the LIN Bus to the Body Control Module (BCM).

When the BCM receives a message to activate the Front Wipers, the BCM provides a ground signal to energize the coil side of the Wiper On/Off Relay, through the Wiper On/Off Relay Control circuit. When the Wiper On/Off Relay is active, a voltage output is sent through the Wiper High/Low Relay to the Wiper Motor, in order to activate the Wiper Motor at low speed. When the BCM receives a message to activate the Front Wipers at high speed, the BCM provides a ground signal to energize the coil side of the Wiper High/Low Relay, through the Wiper High/Low Relay Control circuit. When the Wiper High/Low Relay is active, a voltage output is sent to the Wiper Motor, in order to activate the Wiper Motor at high speed. A ground path for the Wiper Motor is provided through the wiring harness.