Wiper and Washer Systems: Description and Operation
INTRODUCTIONFollowing are general descriptions of the major components in the wiper and washer systems.
SYSTEM OPERATION
Windshield Wiper System
An intermittent windshield wiper system is standard equipment. This system lets the driver select from either of two wiper speeds, or the intermittent wipe mode. The intermittent wipe mode allows the driver to select a delay between wipes of about two seconds to about fifteen seconds.
The windshield wipers will operate only when the ignition switch is in the Accessory or On positions. A fuse located in the fuse block module protects the circuitry of the windshield wiper system.
Windshield Washer System
A electrically operated windshield washer system is standard equipment. A reservoir in the engine compartment holds the washer fluid, which is pressurized by a pump when the windshield washer (multi-function) switch is actuated. The windshield washer pump feeds the pressurized washer fluid through the washer system plumbing to the windshield washer nozzles.
An optional low washer fluid warning lamp on the instrument panel will warn the driver when the washer fluid level needs to be checked.
The washers will operate only when the ignition switch is in the Accessory or On positions. A fuse located in the fuse block module protects the circuitry of the washer system.
Wiper Arm And Blade
All Ram truck models have two 50.8 Centimeter (20-inch) windshield wiper blades with replaceable rubber elements (squeegees) These wiper blades include an anti-lift feature. The wiper blades and squeegees must be oriented correctly when installed on the wiper arms for the anti-lift feature to be effective.
Caution should be exercised to protect the rubber squeegees from any petroleum-based cleaners or contaminants, which will rapidly deteriorate the rubber. If the squeegees are damaged, worn, or contaminated, they must be replaced.
Wiper squeegees exposed to the elements for a long time tend to lose their wiping effectiveness. Periodic cleaning of the squeegees is suggested to remove deposits of salt and road film. The wiper blades, arms, and windshield should be cleaned with a sponge or cloth and windshield washer solvent, a mild detergent, or a non-abrasive cleaner. If the squeegees continue to streak or smear, they should be replaced.
The blades are mounted to two spring-loaded wiper arms. Spring tension of the wiper arms controls the pressure applied to the blades on the glass. The wiper arms are secured by an integral latch to the two wiper pivots on the cowl plenum cover/grille panel at the base of the windshield. The wiper arms and blades cannot be adjusted or repaired. If faulty or damaged, they must be replaced.
Wiper Linkage And Pivot
The wiper linkage and pivot module is secured with screws to the cowl plenum panel beneath the cowl plenum cover/grille panel. The wiper motor is secured with screws to the center of the linkage and pivot module bracket. The wiper pivots are secured to the ends of the module bracket.
The two wiper pivot crank arms and the wiper motor crank arm each have ball studs on their ends. The motor crank arm ball stud is the longer of the three. Two drive links connect the motor crank arm to the pivot crank arms.
The passenger side drive link has a plastic socket- type bushing on each end. The driver side drive link has a plastic socket-type bushing on one end, and a plastic sleeve-type bushing on the other end. The socket-type bushing on one end of each drive link is fit over the ball stud on the crank arm of its respective pivot. The driver side drive link sleeve-type bushing end is then fit over the motor crank arm ball stud, and the other socket-type bushing of the passenger side drive link is snap-fit over the exposed end of the motor crank arm ball stud.
The wiper linkage, pivots, bushings, mounting bracket, and motor are only serviced as a complete unit. If any part of this assembly is faulty or damaged, the entire wiper module must be replaced.
Wiper Motor
The two-speed permanent magnet wiper motor has an integral transmission and park switch. The motor has a rubber-isolated mounting bracket that is secured with bolts to a reinforcement with weld nuts on the engine side of the cowl plenum panel. The wiper motor output shaft passes through the cowl plenum panel into the cowl plenum area, where a nut secures the wiper motor crank arm to the output shaft.
Wiper speed is controlled by current flow to the appropriate set of brushes. The wiper motor completes its wipe cycle when the wiper/washer (multi-function) switch is turned to the Off position, and parks the blades in the lowest portion of the wipe pattern.
The wiper linkage, pivots, bushings, mounting bracket, and motor are only serviced as a complete unit. If any part of this assembly is faulty or damaged, the entire wiper module must be replaced.
Multi-Function Switch:
Wiper Switch And Washer Switch
The windshield wiper and washer switches are contained in the multi-function switch assembly. The multi-function switch assembly is mounted to the left side of the steering column. This switch contains circuitry for the following functions:
- Turn signals
- Hazard warning
- Headlamp beam selection
- Headlamp optical horn
- Windshield wipers
- Windshield washers.
The information contained addresses only the switch functions for the wiper and washer systems. However, the multi-function switch cannot be repaired. If any function of the multi-function switch is faulty, or if the switch is damaged, the entire switch assembly must be replaced.
Intermittent Wipe Module
In addition to low and high speed, the intermittent wipe system has a delay mode. The delay mode has a range of about two to fifteen seconds.
The length of the delay is selected with a variable resistor in the wiper (multi-function) switch, and is accomplished by electronic circuitry within the intermittent wipe module. If the washer knob is depressed while the wiper switch is in the Off position, the intermittent wipe module will operate the wiper motor for approximately two wipes and automatically turn off the motor.
The intermittent wipe module is snap-fit onto a single blade-type mounting bracket located under the instrument panel. The module cannot be repaired and, if faulty, must be replaced.
Washer Reservoir
The washer fluid reservoir is secured to the left side of the radiator fan shroud in the engine compartment. The washer pump and motor unit has a barbed nipple, which is press-fit into a rubber grommet seal inserted in a hole in the bottom of the reservoir.
The reservoir also has a provision for a low washer fluid level sensor. The reservoir and filler cap are each available for service.
Washer Pump
The washer pump and motor are mounted near the bottom of the washer reservoir. A threaded nipple on the pump housing passes through a grommet in the bottom of the reservoir A nut and washer is installed on the nipple from the inside of the reservoir.
A permanently lubricated and sealed motor is coupled to a rotor-type pump. Washer fluid is gravity-fed from the reservoir to the pump. When the motor is energized, the pump pressurizes the washer fluid and forces it through the plumbing to the nozzles.
The washer pump and motor unit cannot be repaired. If faulty, the entire washer pump and motor unit must be replaced.
Washer Nozzle And Plumbing
Pressurized washer fluid is fed through a single hose, attached to a barbed nipple on the washer pump. The hose is routed to a fitting located in the cowl plenum area, beneath the cowl plenum cover/grille panel.
Hoses from the wye fitting are routed to the two nozzles, which are snap-fit into openings in the cowl plenum cover/grille panel. The hoses are clipped to the underside of the cowl plenum cover/grille panel.
The two fluidic washer nozzles are not adjustable. The nozzles and wye fitting cannot be repaired and, if faulty or damaged, they must be replaced.
CIRCUIT OPERATION
Fuse 8 in the fuse block powers the intermittent wiper system. The intermittent wiper system operates at either DELAY, LOW or HIGH speeds.
In the ACCESSORY or RUN position, the ignition switch connects circuit A1 from fuse 3, a 40 amp, in the Power Distribution Center (PDC) with circuit A31. Circuit A31 supplies voltage to circuit V6 through fuse 8 in the fuse block.
Circuit V6 splices to supply power to the wiper switch circuitry in the multi-function switch, the intermittent wiper control module and the park switch in the wiper motor. Ground for the wiper motor is supplied on circuit Z1. Circuit Z3 provides ground for the intermittent wiper control module.
When the operator moves the wiper switch to the LOW speed position, the switch passes voltage to circuit V3. Circuit V3 feeds the wiper motor LOW speed brushes. If the operator selects wiper HIGH speed operation, the wiper switch passes current to circuit V4. Circuit V4 feeds the wiper motor HIGH speed brushes.
If the operator selects wiper DELAY operation, the wiper switch provides an input to the intermittent wiper control module on circuit V9. The DELAY portion of the wiper switch contains a variable resistor. The variable resistor connects to the intermittent wiper module on circuit V9. Voltage for the resistor is supplied by circuit V6 through the wiper switch. The amount of delay selected by the operator determines the voltage drop through the resistor and the voltage level received by the intermittent wiper control module.
Circuit V8 is also an input to the intermittent wiper control module. This input is used by the module as a delay ON input.
After the intermittent wiper control module determines the amount of delay selected, it cycles the wipers by periodically energizing circuit V17 which connects to circuit V3 through the wiper switch. Circuit V3 powers the wiper motor LOW speed brushes.
As the windshield wiper motor turns, the park switch, internal to the motor, moves from its grounded position (down) to the powered RUN (up) position. Circuit V7 provides an input to the intermittent wiper control module when the wiper switch is in the OFF position. The intermittent wiper control module powers the park switch in the wiper motor on circuit V5.
The intermittent windshield wiper system is also equipped with a pulse wipe feature. To activate this feature, the operator presses the washer switch momentarily When the washer switch CLOSES, voltage from circuit V6 passes through the switch to circuit V10. Circuit V10 provides a signal to the intermittent wiper control module and supplies voltage for the windshield washer pump. When the control module receives the signal on circuit V10, it cycles the wipers on circuit V3 while the washer fluid pump operates.
The washer motor operates whenever the washer switch CLOSES and supplies voltage to it on circuit V10. Circuit Z1 provides ground for the pump motor.