Wiper and Washer Systems: Description and Operation

Wiper & 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) control stalk, right (wiper) control stalk 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.
- Rain Sensor - Vehicles equipped with an optional automatic wiper feature have an electronic rain sensor concealed within the base of the rear view mirror unit on the inside of the laminated windshield glass.
- Rain Sensor Control Module - Vehicles equipped with an optional automatic wiper feature have an electronic rain sensor control module located under the lower instrument panel above the accelerator pedal in the passenger compartment of the vehicle.
- 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 duster 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. The wiper relay is a passive component on vehicles equipped with the optional automatic wiper system.
- 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 system functions of this module are passive on vehicles equipped with the optional automatic wiper system.

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.

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:

Two wiper systems are available: the standard intermittent wipe system, or an optional automatic wipe system. 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, either a fixed interval intermittent wipe mode or an auto wipe mode (as the vehicle is equipped), 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.

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. 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.

INTERMITTENT WIPE SYSTEM
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 (run-start) circuit to the intermittent wipe logic circuitry of the wiper, turn signals and engine start control module within the fuse block, the multi-function switch, the wiper relay and the wiper motor park switch. The internal circuitry of the multi-function switch provides a direct hard wired battery current output to the low speed or high speed brushes of the wiper motor when the Low, High, 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 of the wiper, turn signals and engine start control module 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 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 on/off relay output 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 the fused ignition switch output (run-start) circuit. The intermittent wipe logic circuit energizes the wiper relay and the wiper on-off relay output 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 washer switch circuitry directs battery current 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 on-off relay output circuit, which allows it to monitor the number of wiper blade sweeps. After the appropriate number of wiper sweeps the intermittent wipe logic circuitry operates the wiper motor to return the wipers to their park position, then de-energizes the wiper relay.

AUTOMATIC WIPE SYSTEM
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 (run-start) circuit to the rain sensor control module under the instrument panel, to the rain sensor within the base of the inside rear view mirror on the windshield, and to the multi-function switch. The internal circuitry of the multi-function switch provides direct hard wired battery current outputs to the rain sensor control module to indicate the selected wiper operating mode. The control module logic monitors the inputs from the multifunction switch as well as from the rain sensor and the wiper motor park switch in order to provide the outputs necessary to operate the wiper motor and the washer pump motor as requested.

When the automatic wipe position is selected with the multi-function switch control stalk, the rain sensor control module logic circuitry responds by providing an acknowledgment sweep of the wipers. The rain sensor calculates the correct wiper speed and wiper sweep intervals required to remove the moisture detected on the windshield glass and provides this input to the rain sensor control module. The control module then energizes and de-energizes the wiper motor automatically. The automatic wipe logic will also provide a wipe-after-wash feature to clear washer fluid that is directed onto the windshield when the washer system is utilized.

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, and the rain sensor control module logic circuit de-energizes the wiper motor. If the wiper blades are not in the down position at the moment the Off position is selected, the park switch is an open circuit. The control module logic circuit directs battery current to the low speed brush of the wiper motor, which 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 with the wiper system turned Off, the rain sensor control module logic circuitry operates the wiper motor in the same manner as it does to provide the automatic wipe mode operation. After the state of the washer switch changes to open the control module 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 control module operates the wiper motor to return the wipers to their park position, then de-energizes the wiper motor.

OPERATING MODES
The components of the wiper and washer system are designed to provide the following operating modes:
- Automatic Wipe Mode - On vehicles so equipped, the internal circuitry of the multi-function switch, the rain sensor control module and the rain sensor work in concert to provide wiper system operation automatically whenever moisture is detected on the windshield glass.
- Continuous Wipe Mode-The two-speed wiper motor, the internal circuitry of the multi-function switch, and the wiper system logic circuits work in concert to provide two continuous wipe cycles, low speed or high speed.
- Intermittent Wipe Mode - On vehicles so equipped, 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 system logic circuits 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 wiper system logic circuitry provides 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.