Front Wiper And Washer System: Operation
The front wiper and washer system is designed to provide the vehicle operator with a convenient, safe, and reliable means of maintaining visibility through the windshield glass. The various components of this system are designed to convert electrical energy produced by the vehicle electrical system into the mechanical action of the wiper blades to wipe the outside surface of the glass, as well as into the hydraulic action of the washer system to apply washer fluid stored in an on-board reservoir to the area of the glass to be wiped. When combined, these components provide the means to effectively maintain clear visibility for the vehicle operator by removing excess accumulations of rain, snow, bugs, mud or other minor debris from the outer surface of the windshield glass that might be encountered while driving the vehicle under numerous types of inclement operating conditions.
The vehicle operator initiates all front wiper and washer system functions with the control stalk (1) of the right (wiper) multifunction switch that extends from the right side of the steering column, just below the steering wheel. Moving the control stalk to a detent position selects the OFF, Delay (Intermittent), Continuous LO or Continuous HI front wiper system operating modes. While the control stalk is in the Delay position, the control knob (3) on the end of the control stalk selects one of four speed sensitive delay intervals.
Lifting the control stalk to a momentary upward position selects the MIST (or Pulse) mode, which cycles the wiper blades for as long as the switch is held closed then completes the current wipe cycle and parks the blades at the base of the windshield after the switch is released. Pulling the control stalk rearward toward the steering wheel to a momentary position actuates the front washer system switch, which selects the front Wash mode and dispenses washer fluid in the wipe pattern on the windshield for as long as the switch is held closed.
The right multifunction switch provides Controller Area Network - Chassis (CAN-C) and Local Interface Network (LIN) inputs to the BCM for all of the wiper and washer system functions. The BCM then provides the appropriate hardwired control outputs to energize or de-energize the wiper and washer relays soldered to its printed circuit board. The relays control the flow of battery current to the front wiper motor and the washer pump motor, invoking the requested wiper and washer system operating modes. Front wiper and washer system operation is completely controlled by the BCM logic circuits, and that logic will only allow these systems to operate when the status of the ignition switch is Accessory or ON.
The hardwired circuits and components of the front wiper and washer system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the front wiper and washer system or the electronic controls and communication between other modules and devices that provide some features of the front wiper and washer system. The most reliable, efficient and accurate means to diagnose the front wiper and washer system or the electronic controls and communication related to front wiper and washer system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.