Wiper and Washer Systems: Description and Operation

Wiper And Washer System:

An electrically operated intermittent wiper and washer system is standard factory-installed safety equipment on this model. The wiper and washer system includes the following major components, which are described in further detail elsewhere in this service information:
- Check Valve - The washer system check valve is integral to the plumbing fitting located in the washer plumbing between the cowl plenum washer hose and the two washer nozzle hoses, and is located beneath the cowl top panel at the base of the windshield in the engine compartment.
- Multi-Function Switch - The multi-function switch is secured to the top of the steering column, just below the steering wheel. Only the left (lighting), right (wiper) control stalks and the hazard warning switch button for the multi-function switch are visible, the remainder of the switch is concealed beneath the steering column shrouds. The multi-function switch contains all of the switches for both the wiper and washer systems
- Washer Fluid Level Switch - The optional washer fluid level switch is integral to a unique version of the washer pump/motor unit, which is located in a dedicated hole on the top of the sump area near the back of the windshield washer reservoir on the right front fender wheel house in the engine compartment.
- Washer Nozzle - A single washer nozzle with three separate orifices is secured with integral snap features to each wiper arm. The hoses for the washer nozzles are concealed beneath a molded plastic guide on the underside of each wiper arm and routed to the engine compartment through unique molded plastic elbow fittings located near each wiper pivot at the base of the windshield.
- Washer Pump/Motor - Two different washer pump/motor units are available for this model. One version has an integral washer fluid level switch that provides a hard wired input to the instrument cluster for control of the optional washer fluid indicator. The washer pump/motor unit is located in a dedicated hole on the top of the sump area near the back of the windshield washer reservoir on the right front fender wheel house in the engine compartment.
- Washer Reservoir - The washer reservoir is located on the right front fender wheel house in the engine compartment. The washer reservoir filler is accessed from the right front corner of the engine compartment.
- Wiper Arm - The two unequal length wiper arms are secured to the two wiper pivots, which extend through the cowl panel near the base of the windshield. The longer arm is installed on the left (driver) side of the windshield.
- Wiper Blade - The two unequal length wiper blades are secured to the two wiper arms, and are parked on the glass near the bottom of the windshield when the wiper system is not in operation. The longer blade is installed on the left (driver) side of the windshield.
- Wiper Linkage - The wiper pivots are the only visible components of the wiper linkage. The remainder of the linkage is concealed within the engine compartment just behind the hood opening. The wiper linkage module includes the two wiper drive links, the wiper motor crank arm, the two wiper pivots, and the linkage and motor mounting bracket.
- Wiper Motor - The wiper motor is secured to the wiper linkage module bracket on the underside of the cowl panel within the engine compartment. The wiper motor output shaft and crank arm extend through a clearance hole in the mounting bracket, where they are connected to a crank arm that drives the wiper linkage.
- Wiper Relay - The wiper relay is located in a dedicated receptacle on the lower left surface of the fuse block underneath the steering column behind the fuse access panel and the steering column opening panel.
- Wiper, Turn Signals, Engine Start Control Module - The wiper, turn signals and engine start control module is integral to the fuse block located underneath the steering column. The fuse block is concealed behind the fuse access panel and the steering column opening panel, where it is secured with screws to the steering column. The wiper, turn signals and engine start control module contains the intermittent wipe logic circuitry, which includes active electronic elements that allow it to provide the intermittent wipe delay and the wipe-after-wash features of the intermittent wipe system based upon numerous hard wired inputs, then provides the proper programmed hard wired control output to operate the wiper motor through the wiper relay.

Hard wired circuitry connects the 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 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.

OPERATING MODES
The components of the wiper and washer system are designed to provide the following operating modes:
- Continuous Wipe Mode - The two-speed wiper motor, the internal circuitry of the multi-function switch, and the wiper relay work in concert to provide two continuous wipe cycles, low speed or high speed.
- Intermittent Wipe Mode - The internal circuitry of the multi-function switch, the intermittent wipe circuitry of the wiper, turn signals and engine start control module in the fuse block, and the wiper relay work in concert to provide an intermittent wipe mode with a single, fixed delay interval.
- Pulse Wipe Mode - The internal circuitry of the multi-function switch and the wiper relay work in concert to provide a pulse wipe mode that will allow the wiper motor to be operated for a single, complete wipe cycle.
- Washer Mode - When the washer system is activated with the multi-function switch while the wiper system is operating, washer fluid will be dispensed onto the windshield glass through the washer nozzles for as long as the washer pump/motor is energized.
- Wipe-After-Wash Mode - The intermittent wipe circuitry of the wiper, turn signals and engine start control module in the fuse block, and the wiper relay provide a wipe-after-wash feature. If the wipers are turned Off, this feature will operate the washer pump/motor and the wipers for as long as the washer system is activated, then provide several additional wipe cycles after the washer system is deactivated before parking the wiper blades near the base of the windshield.

The 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.

Windshield Wiper/Washer Switch:

The vehicle operator initiates all wiper and washer system functions with the multi-function switch wiper control stalk that extends from the right side of the steering column, just below the steering wheel. Depressing, raising, or pulling the right control stalk of the multi-function switch selects the desired wiper system operating mode. The wiper system allows the vehicle operator to select from two continuous wiper speeds, Hi or Lo, a fixed interval intermittent wipe mode, and a pulse wipe mode. Pushing the knob on the end of the control stalk towards the steering column activates the washer pump/motor, which dispenses washer fluid onto the windshield glass through the washer nozzles.

When the ignition switch is in the On position, battery current from a fuse in the fuse block underneath the steering column is provided through a fused ignition switch output circuit to the wiper motor park switch, the intermittent wipe logic circuitry of the wiper, turn signals and engine start control module within the fuse block, the wiper relay, and the multifunction switch. The internal circuitry of the multifunction switch provides a direct hard wired battery current output to the low speed or high speed brushes of the wiper motor when the Lo, Hi, or Pulse position is selected, which causes the wipers to cycle at the selected speed for as long as that switch position remains selected.

In order to provide the intermittent wipe and wipe-after-wash features, the intermittent wipe logic circuitry within the fuse block monitors inputs from the intermittent wipe and washer switch circuitry of the multi-function switch and the park switch in the wiper motor. When the intermittent wipe position is selected with the multi-function switch control stalk, the intermittent wipe logic circuitry within the fuse block responds by energizing the wiper relay and calculating the correct delay interval. The energized wiper relay directs battery current through the intermittent wipe position circuitry of the multi-function switch to the low speed brush of the wiper motor. The intermittent wipe logic circuit monitors the wiper motor operation through the wiper park switch sense circuit, which allows it to determine the proper timing to begin the next wiper blade sweep. The normal delay interval is about five seconds.

When the Off position of the multi-function switch wiper control stalk is selected, one of two events is possible. The event that will occur depends upon the position of the wiper blades on the windshield at the moment that the 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 wiper motor is closed to ground, the intermittent wipe logic circuit de-energizes the wiper relay, 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 a fused ignition switch output circuit. The intermittent wipe logic circuit energizes the wiper relay and the park switch sense circuit directs battery current to the low speed brush of the wiper motor through the normally open contact of the wiper relay, then through the internal Off position circuitry of the multi-function 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.

When the Wash position of the control knob on the right control stalk of the multi-function switch is selected, the Wash position circuitry within the switch directs a battery current signal input to the washer pump motor, and to the intermittent wipe logic circuitry. When the washer switch is closed with the wiper system turned Off, the intermittent wipe logic circuitry operates the wiper motor in the same manner as it does to provide the intermittent wipe mode operation. After the state of the washer switch changes to open, the intermittent wipe logic circuitry monitors the wiper motor through the wiper park switch sense circuit, which allows it to monitor the number of wiper blade sweeps. After the appropriate number of wiper sweeps, the intermittent wipe logic circuitry de-energizes the wiper relay once the wiper motor returns the wipers to their park position.

The hard wired inputs to and outputs from the wiper and washer system components may be diagnosed and tested using conventional diagnostic tools and methods. Proper testing of the intermittent wipe logic circuitry within the fuse block requires the use of a DRBIII(R) scan tool. Refer to the appropriate diagnostic information. Refer to the owner's manual in the vehicle glove box for more information on the features and operation of the wiper and washer system.