Principles of Operation

Wipers and Washers

Principles of Operation

Windshield Wiper Operation

The multifunction switch is mounted to the Steering Column Control Module (SCCM). The SCCM commands the windshield wiper motor to activate the appropriate wash, low, high and intermittent modes through a private Local Interconnect Network (LIN).

When the multifunction switch is in the HIGH position, the windshield wiper motor also receives a ground signal which is hardwired directly through the SCCM (bypassing the logic within the module). This fail-safe circuit makes sure that the windshield wipers will function in HIGH speed mode in the event of a LIN communication failure.

Washer System

When the multifunction switch is placed in the WASH position, the SCCM sends the request to the windshield wiper motor through the LIN. The windshield wiper motor supplies voltage to the washer pump, which then directs washer fluid to the windshield.

Speed Dependent Wipers (if equipped)

When the multifunction switch is in any intermittent setting except the INT 1 position, the speed-dependent function increases the frequency of wiping to compensate for the extra moisture that accumulates on the windshield as the vehicle's speed increases. The SCCM receives Vehicle Speed Sensor (VSS) information from the Body Control Module (BCM) through the High Speed Controller Area Network (HS-CAN). The SCCM sends the VSS information to the windshield wiper motor through the LIN.

Wiper Activated Headlamps (if equipped)

If equipped with automatic headlamps, the SCCM sends a message to the BCM over the HS-CAN to illuminate the exterior lamps within 10 seconds of the windshield wipers being activated by the multifunction switch when the headlamp control switch is in the AUTOLAMP position. The BCM continues to illuminate the exterior lamps for approximately 30 seconds after the windshield wipers have been turned off.