Principles of Operation (How Does it Work?)

The front wipers and washer are controlled by the Front Electronic Module (FEM). The front washer/wiper portion of the multifunction switch is hardwired to the FEM. When the switch is moved to the desired position, the FEM processes this information and outputs the appropriate command(s) to one of several hardwired relays which control the front wiper motor speeds or front washer pump actuation. Fault management of the front wiper provides limited front wiper functionality in the event of a failure of the front wiper/washer switch or an ignition switch failure transmitted by the instrument cluster module.

Intermittent wiper speed control can vary dependent upon vehicle speed. This is accomplished by the FEM receiving vehicle speed information from the anti-lock brake control module, and throttle position status from the PCM. When the front wiper/washer switch is in any of the intermittent positions, the FEM will process the information from the PCM and anti-lock brake control module and decrease the wiper delay time when the vehicle is above 16 km (10 miles) per hour.

The front washer pump is hardwired to the FEM which will actuate the pump when the front wiper/washer portion of the multifunction switch is moved to the wash position.

The rear wiper and washer are controlled by the FEM. The rear wiper/washer portion of the multifunction switch is hardwired to the FEM. When the switch is moved to the desired position, the FEM processes this information and outputs the appropriate command(s) to a hardwired relay which controls the rear wiper motor speeds, and rear washer pump actuation.