Front Wipers & Washers
FRONT WIPERS/WASHERSFig. 1 Front Wiper & Washer System:
An electrically operated intermittent front wiper and washer system is standard factory-installed safety equipment on this model. The front wiper and washer system includes the following major components, which are described in further detail elsewhere in this service information:
- Front Check Valve - The front washer system check valve is located in the washer plumbing on the underside of the hood panel between the cowl and the front washer nozzle.
- Front Washer Nozzle - The single fluidic front washer nozzle is secured by an integral latch feature to a dedicated opening near the rear of the hood panel. The washer plumbing fitting for the washer nozzle is concealed beneath the hood panel.
- Front Washer Pump/Motor - The front washer pump/motor unit is located in a dedicated hole on the lower inboard side of the washer reservoir, on the top of the left front wheel house in the engine compartment. The front washer pump/motor unit is located below and forward of the optional rear washer pump/motor unit mounting hole.
- Front Washer Plumbing - The plumbing for the front washer system consists of rubber hoses and molded plastic fittings. The plumbing is routed along the left side of the engine compartment from the washer reservoir, and up the cowl panel to the hood panel rear reinforcement. Then along the hood panel rear reinforcement to the front washer nozzle fitting.
- Front Wiper Arm - The two front wiper arms are secured with integral latches to the serrated ends of the two wiper pivot shafts, which extend through the cowl plenum cover/grille panel located near the base of the windshield.
- Front Wiper Blade - The two front wiper blades are secured to the two front wiper arms with integral latches, and are parked on the glass near the bottom of the windshield when the front wiper system is not in operation.
- Front Wiper Module - The front wiper pivot shafts are the only visible components of the front wiper module. The remainder of the module is concealed within the cowl plenum area beneath the cowl plenum cover/grille panel. The front wiper module includes the wiper module bracket, three rubber-isolated wiper module mounts, the front wiper motor, the front wiper motor crank arm, the front wiper drive link, the front wiper connector link, and the two front wiper pivots.
- Right Multi-Function Switch - The right multi-function switch is located near the top of the steering column, just below the steering wheel. The right multi-function switch includes a control stalk with a control knob on the end that extends through a dedicated opening on the right side of the steering column shrouds. The right multi-function switch is dedicated to providing all of the driver controls for the front wiper and washer systems.
- Washer Reservoir - The molded plastic washer reservoir is secured by two screws through integral mounting tabs to the top of the left front fender wheel house, in the left front corner of the engine compartment. The washer reservoir filler neck is accessed from the left front corner of the engine compartment.
Hard wired circuitry connects the front wiper and washer system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the front wiper and washer system components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
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 outside windshield glass surface 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 and control knob of the right multi-function switch that extends from the right side of the steering column, just below the steering wheel. Moving the control stalk upward selects the front wiper system operating mode. The front wiper system allows the vehicle operator to select from two continuous wiper speeds, High or Low, or the intermittent wipe Delay mode. Pulling the control stalk downwards and releasing it selects the front wiper system Mist mode, which operates the front wipers for one complete wipe cycle after the control stalk is released. Rotating the control knob on the end of the control stalk allows the vehicle operator to select the intermittent wipe Delay interval. Pulling the control stalk towards the steering wheel activates the front washer pump/motor, which dispenses washer fluid onto the windshield glass through the front washer nozzle.
When the ignition switch is in the Accessory or On positions, battery current from a fuse in the Power Distribution Center (PDC) is provided to the front wiper and washer system fuse in the fuse block. This fuse provides battery current through separate fused ignition switch output (run-acc) circuits to the right multi-function switch, and to the front wiper motor. Within the right multi-function switch, this battery current is fed to one side of the control coil in the wiper motor relay, and to the electronic intermittent wipe logic circuit, which are both integral to the switch.
The intermittent wipe and wipe-after-wash features of the front wiper and washer system are both provided by the electronic intermittent wipe logic circuit within the right multi-function switch. In order to provide the intermittent wipe feature, the logic circuit monitors the wiper switch state, the intermittent delay resistance setting, and the wiper motor park switch state. In order to provide the wipe-after-wash feature, the logic circuit monitors both the front washer switch state and the wiper motor park switch state.
The hard wired circuits and components of the front wiper and washer system may be diagnosed and tested using conventional diagnostic tools and procedures. However, conventional diagnostic methods are not possible in the diagnosis of the intermittent wipe mode circuitry and logic within the right multi-function switch. If the front wiper and washer system operates satisfactorily in all modes except the
Delay mode, the faulty right multi-function switch must be replaced. Refer to the appropriate diagnostic information.
OPERATING MODES
The components of the wiper and washer system are designed to work in concert to provide the following operating modes:
- Continuous Wipe Modes - The control stalk of the right multi-function switch has two continuous wipe positions, Low and High. When selected, these switch positions will cause the two-speed wiper motor to operate in a continuous low or high speed cycle.
- Intermittent Wipe Mode - The control stalk of the right multi-function switch has an intermittent wipe position, and the control knob has several minor detent positions which will each cause the wiper system to operate at different delay intervals between complete wipe cycles. The internal circuitry of the right multi-function switch provides the intermittent wipe mode and adjustable delay intervals between wipe cycles of about one second to about fifteen seconds.
- Mist Wipe Mode - The control stalk of the right multi-function switch has a momentary mist wipe position that will operate the front wipers for a single complete cycle, then park the wiper blades near the base of the windshield.
- Washer Mode - When the control stalk of right multi-function switch is pulled toward the steering wheel to the momentary Wash position while the front wiper system is operating, washer fluid will be dispensed onto the windshield glass through the washer nozzles for as long as the front washer pump is energized.
- Wipe-After-Wash Mode - When the control stalk of right multi-function switch is pulled toward the steering wheel to the momentary Wash position while the front wiper system is not operating, the internal circuitry of the right multi-function switch provides a wipe-after-wash feature which will operate the front washer pump/motor and the front wipers for as long as the washer system is activated, then provide one or two additional wipe cycles after the washer system is deactivated before parking the front wiper blades near the base of the windshield.
Following are paragraphs that briefly describe the operation of each of the front wiper and washer system operating modes.
CONTINUOUS WIPE MODE
When the Low position of the right multi-function switch control stalk is selected, the Low mode circuitry within the switch directs battery current to the low speed brush of the front wiper motor, which causes the front wipers to cycle at a low speed. When the High position of the control stalk is selected, the High mode circuitry within the switch directs battery current to the high speed brush of the front wiper motor, which causes the front wipers to cycle at a high speed.
When the Off position of the right multi-function switch control stalk is selected, one of two events is possible. The event that occurs depends upon the position of the wiper blades on the windshield at the moment that the control stalk Off position is selected. If the wiper blades are in the down position on the windshield when the Off position is selected, the park switch that is integral to the front wiper motor is closed to ground and the wiper motor ceases to operate.
If the wiper blades are not in the down position on the windshield at the moment the Off position is selected, the park switch is closed to battery current through the fused ignition switch output (run-acc) circuit of the front wiper motor. The park switch sense circuit directs this battery current to the low speed brush of the wiper motor through the normally closed circuit of the wiper motor relay and the Off mode circuitry of the wiper switch. This causes the wiper motor to continue running until the wiper blades are in the down position on the windshield and the park switch is again closed to ground.
INTERMITTENT WIPE MODE
When the control stalk of the right multi-function switch is moved to the Delay position, the Delay mode circuitry within the switch directs battery current to a request input of the integral logic circuit. The Delay mode circuitry also directs battery current through an internal variable resistor to the intermittent wipe delay sense input of the logic circuit, which indicates the delay interval that has been selected by the vehicle operator using the control knob on the end of the right multi-function switch control stalk.
The logic circuit responds to the Delay mode request inputs by calculating the correct delay interval. The logic circuit then energizes the wiper motor relay by pulling the relay control coil to ground. The energized wiper motor relay directs battery current from the normally open relay terminal through the common feed relay terminal and the Delay mode wiper switch circuitry to the low speed brush of the wiper motor. The logic circuit monitors the front wiper motor operation through the wiper park switch sense circuit, which allows the logic circuit to determine the proper timing to begin the next wiper blade sweep.
MIST MODE
When the control stalk of the right multi-function switch is moved to the momentary Mist position, the Mist mode circuitry within the switch directs battery current to the low speed brush of the front wiper motor, which causes the front wipers to cycle at low speed for as long as the switch is held in the Mist position. When the control stalk is released, the wiper motor completes the current wipe cycle then parks the wiper blades near the base of the windshield.
WASH MODE
When the momentary Wash position of the right multi-function switch control stalk is selected while the front wiper system is operating, the Wash mode circuitry within the switch directs battery current to the front washer pump/motor for as long as the Wash mode circuitry within the switch remains closed. When the control stalk is released the Wash mode circuitry within the switch opens and the front washer pump/motor ceases operation.
WIPE-AFTER-WASH MODE
When the washer switch is closed with the front wiper system turned Off, the intermittent wipe logic circuit operates the front wiper motor through the wiper motor relay in the same manner as it does to provide the Delay mode operation, but uses the Off mode circuitry of the wiper switch to feed battery current to the low speed brush of the front wiper motor. When the Wash mode circuitry state changes to open, the intermittent wipe logic circuit de-energizes the front washer pump/motor unit, but allows the wiper motor to operate for several additional wipe cycles before it de-energizes the wiper motor and parks the wiper blades near the base of the windshield. The intermittent wipe logic circuit monitors the front wiper motor through the wiper park switch sense circuit, which allows the logic circuit to count the number of wiper blade sweeps.