Part 2B

Fig.3 Rear Check Valve:

REAR CHECK VALVE
Models equipped with the optional rear wiper and washer system have a check valve installed in the rear washer system plumbing. The check valve is located at the highest point of the rear washer supply hose routing and is connected between the body and liftgate sections of the rear washer supply hose, beneath the liftgate opening upper header garnish molding. The check valve consists of a molded plastic valve body with a raised center section that is tapered in the direction of the flow through the valve. A barbed hose nipple is formed on each side of the raised center section of the valve body. Within the check valve body, a small check ball is held against an integral valve seat at one end of the valve by a small coiled spring. The rear check valve cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The rear check valve provides more than one function in this application. It serves as an in-line connector fitting between the body and liftgate sections of the rear washer supply hose. It also prevents washer fluid from draining out of the rear washer Supply hoses back to the washer reservoir. This drain-back would result in a lengthy delay from when the rear washer switch is actuated until washer fluid was dispensed through the rear washer nozzle, because the rear washer pump would have to refill the rear washer plumbing from the reservoir to the nozzle. Finally, the rear check valve prevents washer fluid from siphoning through the rear washer nozzle after the rear washer system is turned OFF. When the rear washer pump pressurizes and pumps washer fluid from the reservoir through the rear washer plumbing, the fluid pressure overrides the spring pressure applied to the check ball within the valve and unseats the check ball, allowing washer fluid to flow toward the rear washer nozzle. When the rear washer pump stops operating, spring pressure seats the check ball in the valve and fluid flow in either direction within the rear washer plumbing is prevented.

REAR WASHER HOSES/TUBES
The rear washer plumbing consists of a small diameter rubber hose that is integral to and routed with the headlamp and dash wire harness from the barbed outlet nipple of the rear washer pump/motor on the washer reservoir through the dash panel to the left cowl side panel under the instrument panel. The washer hose passes from the engine compartment into the passenger compartment through a dedicated hole near the left side of the dash panel. Near the left cowl side panel, the washer hose is connected with a molded plastic in-line connector fitting to another hose that is integral to and routed with the body wire harness down the left door sill, across the floor panel under the rear seat cushion to the right rear wheel house, then over the wheel house to the right liftgate pillar. Near the base of the right liftgate pillar, the washer hose is connected with another molded plastic in-line connector fitting to the liftgate pillar washer hose.

Fig.7 Rear Washer Plumbing:

The liftgate pillar washer hose is routed up through the right liftgate pillar and the upper liftgate opening reinforcement to the rear check valve located near the center of the upper liftgate opening. A liftgate washer hose is connected to the other side of the check valve and passes from the upper liftgate opening to the liftgate through a plastic convolute tube. The liftgate washer hose is then routed across the top, down the right side, and back to the center of the liftgate around the liftgate glass opening. Near the center of the liftgate, the washer hose is connected to a nipple that protrudes from the inside of the rear wiper motor output shaft bezel. The washer fluid passes through the bezel nipple to the outside of the liftgate panel.

Washer hose is available for service only as roll stock, which must then be cut to length. For service replacement of the hose that is integral to the headlamp and dash or body wire harnesses, it is suggested that a suitable length of washer hose be carefully routed along and secured to the outside of the harness. The molded plastic washer hose fittings cannot be repaired. If these fittings are faulty or damaged, they must be replaced.

Washer fluid in the washer reservoir is pressurized and fed by the rear washer pump/motor through the rear washer system plumbing and fittings to the rear washer nozzle on the rear wiper arm. Whenever routing the washer hose or a wire harness containing a washer hose, it must be routed away from hot, sharp, or moving parts; and, sharp bends that might pinch the hose must be avoided.

Fig.8 Rear Washer Nozzle:

REAR WASHER NOZZLE
The rear washer nozzle is snapped onto the rear wiper arm, near the wiper blade. The rear washer nozzle is constructed of molded plastic and has a small pin molded into its underside that fits into a small socket stamped into the wiper arm to keep it properly located on the arm. A short length of washer hose is connected to a barbed nipple on the washer nozzle just below the wiper arm. The hose is routed along the underside of the wiper arm toward the pivot end of the arm. A small plastic trough-like retainer secures the washer hose to the underside of the wiper arm just above the stamped steel channel that conceals the wiper arm spring. The washer hose is then routed through the wiper arm spring to the pivot end of the arm, where it is connected to a barbed nipple located near the bottom of the wiper motor output shaft bezel on the outside of the liftgate panel. The rear washer nozzle cannot be adjusted or repaired. If the nozzle, is faulty or damaged, it must be replaced.

The rear washer nozzle is designed to dispense washer fluid into the wiper pattern area on the outside of the liftgate glass. Pressurized washer fluid is fed to the nozzle from the washer reservoir by the rear washer pump/motor through a single hose, which is attached to a barbed nipple on the rear washer nozzle below the rear wiper arm. Because the washer nozzle is secured to the rear wiper arm, it is able dispense pressurized washer fluid onto the liftgate glass and effectively covers a larger area of the glass area to be cleaned.

Fig.11 Washer Reservoir:

REAR WASHER PUMP/MOTOR
The rear washer pump/motor unit is located on the outboard side and near the front of the washer reservoir, between the left front inner and outer fender panels. A small permanently lubricated and sealed electric motor is coupled to the rotor-type washer pump. A seal flange with a barbed nipple on the pump housing passes through a rubber grommet seal installed in one of two dedicated mounting holes near the bottom of the washer reservoir. The rear washer pump/motor unit is always mounted in the upper pump mounting hole of the reservoir. The washer pump/motor unit is retained on the reservoir by the interference fit between the barbed pump nipple and the grommet seal, which is a light press fit. The rear washer pump/motor unit cannot be repaired. If faulty or damaged, the entire washer pump/motor unit must be replaced.

The rear washer pump/motor unit is connected to the vehicle electrical system through a single take out and two-cavity connector of the headlamp and dash wire harness. The washer pump/motor is grounded at all times through a take out of the headlamp and dash wire harness with a single eyelet terminal connector that is secured under a ground screw to the top of the left front fender wheel housing in the engine compartment. The rear washer pump/motor receives battery current through the closed contacts of the momentary rear washer switch within the rear wiper and washer switch unit only when the bottom of the switch rocker is pushed towards the instrument panel. Washer fluid is gravity-fed from the washer reservoir to the inlet side of the washer pump. When the pump motor is energized, the rotor-type pump pressurizes the washer fluid and forces it through the pump outlet nipple, the rear washer plumbing, and the rear washer nozzle onto the liftgate glass.

Fig.14 Rear Wiper Arm:

REAR WIPER ARM
The rear wiper arm is the rigid member located between the rear wiper motor output shaft that protrudes from the outer liftgate panel near the base of the liftgate glass opening and the wiper blade on the liftgate glass. This wiper arm features an over-center hinge that allows easy access to the liftgate glass for cleaning. The wiper arm has a die cast metal pivot end. This pivot end has a hole in it with internal serrations and a plastic pivot cover is secured loosely to and pivots on the wiper arm hinge pin to conceal the wiper arm retaining nut. The wide end of a tapered, stamped steel channel is secured with a hinge pin to the pivot end of the wiper arm. One end of a long, rigid, stamped steel strap, with a small hole near its pivot end, is riveted and crimped within the narrow end of the stamped steel channel. The tip of the wiper blade end of this strap is bent back under itself to form a small hook. Concealed within the stamped steel channel, one end of a long spring is hooked through a hole in a small stamped steel strap on the hinge pin within the die cast pivot end, while the other end of the spring is hooked through the small hole in the steel strap. The entire wiper arm has a satin black finish applied to all of its visible surfaces.

A wiper arm cannot be adjusted or repaired. If damaged or faulty, the entire wiper arm unit must be replaced.

The rear wiper arm is designed to mechanically transmit the motion from the rear wiper motor output shaft to the rear wiper blade. The wiper arm must be properly indexed to the motor output shaft in order to maintain the proper wiper blade travel on the glass. The hole with internal serrations in the wiper arm pivot end interlocks with the serrations on the outer circumference of the motor output shaft, allowing positive engagement and finite adjustment of this connection. A hex nut secures the wiper arm pivot end to the threads on the motor output shaft and the pivot cover hinges and snaps over this connection for a neat appearance. The spring-loaded wiper arm hinge controls the down-force applied through the tip of the wiper arm to the wiper blade on the glass. The hook formation on the tip of the wiper arm provides a cradle for securing and latching the wiper blade pivot block to the wiper arm.

Wiper Blade Remove/Install - Typical:

REAR WIPER BLADE
The rear wiper blade is secured by an integral latching pivot block to the hook formation on the tip of the rear wiper arm, and rests on the glass near the base of the liftgate glass when the wiper is not in operation. The wiper blade consists of the following components:
- Superstructure - The superstructure includes a stamped steel bridge and plastic links with claw formations that grip the wiper blade element. Also included in this unit is the latching, molded plastic pivot block that secures the superstructure to the wiper arm. All of the metal components of the wiper blade have a satin black finish applied.
- Element - The wiper element or squeegee is the resilient rubber member of the wiper blade that contacts the glass.
- Flexor - The flexor is a rigid metal component running along the length of each side of the wiper element where it is gripped by the claws of the superstructure.

All Cherokee models with the optional rear wiper and washer system have one 33.0-centimeter (13-inch) rear wiper blade with a non-replaceable element (squeegee). The wiper blade cannot be adjusted or repaired. If faulty, worn, or damaged the entire wiper blade unit must be replaced.

The wiper blade is moved back and forth across the glass by the wiper arm when the wiper system is in operation. The wiper blade superstructure is the flexible frame that grips the wiper blade element and evenly distributes the force of the spring-loaded wiper arm along the length of the element. The combination of the wiper arm force and the flexibility of the superstructure makes the element conform to and maintain proper contact with the glass, even as the blade is moved over the varied curvature found across the glass surface. The wiper element flexor provides the claws of the blade superstructure with a rigid, yet flexible component on the element which can be gripped. The rubber element is designed to be stiff enough to maintain an even cleaning edge as it is drawn across the glass, but resilient enough to conform to the glass surface and flip from one cleaning edge to the other each time the wiper blade changes directions.

Fig.21 Rear Wiper Module:

REAR WIPER MODULE
The rear wiper module is concealed within the liftgate, below the liftgate glass and behind the liftgate trim panel. The end of the motor output shaft that protrudes through the liftgate outer panel to drive the rear wiper arm and blade is the only visible component of the rear wiper module. A rubber gasket, a plastic bezel with an integral washer hose in-line connector, and a nut seals and secures the motor output shaft to the liftgate outer panel. The rear wiper module consists of the following major components:
- Bracket - The rear wiper module bracket consists of a stamped steel mounting plate for the wiper motor that is secured with screws to the wiper motor and to the liftgate inner panel.
- Motor - The single-speed permanent magnet rear wiper motor is secured with screws to the rear wiper module bracket. The wiper motor includes an integral transmission, a motor output shaft, the rear wiper module circuitry, a diode, and the rear wiper motor park switch.

The rear wiper module cannot be adjusted or repaired. If any component of the module is faulty or damaged, the entire rear wiper module unit must be replaced. The motor output shaft gasket, bezel, and nut are available for service replacement.

The rear wiper module operation is controlled by the vehicle operator through battery current inputs received by the rear wiper module circuit board from the rear wiper and washer switch on the instrument panel. The wiper blade cycling is controlled by the rear wiper module circuit board, which controls current flow to the wiper motor brushes. The park switch is a single pole, single throw, momentary switch within the wiper motor that is mechanically actuated by the wiper motor transmission components. The park switch alternately closes the wiper motor brush to the module circuit board output or to a fused ignition switch output (run) circuit, depending upon the position of the wiper on the glass. This feature allows the motor to complete its current wipe cycle after the wiper system has been turned OFF, and to park the wiper blade in the lowest portion of the wipe pattern. An internal diode protects the module circuit board from feedback through the park switch when the switch is closed to the fused ignition switch output (run) circuit. The wiper motor transmission converts the rotary output of the wiper motor to the back and forth wiping motion of the rear wiper arm and blade on the liftgate glass.

Fig.24 Accessory Switch Bezel:

REAR WIPER & WASHER SWITCH
The rear wiper and washer switch is located in the accessory switch bezel near the bottom of the instrument panel center stack area on the instrument panel. The single two-function switch is molded from black plastic and is secured by a snap fit in a dedicated receptacle molded into the back of the accessory switch bezel. A single six pin connector receptacle is molded into the back of the switch housing. Only the switch rocker button is visible through the lower opening of the instrument panel center bezel, the remainder of the switch is concealed behind the accessory switch bezel within the instrument panel. The rear wiper and washer switch contains switches to control both the rear wiper and the rear washer, and also has an integral incandescent illumination lamp with a serviceable bulb. The switch rocker is identified with an International Control and Display Symbol icon for windshield wiper and washer, and the icon is illuminated from behind when the exterior lamps are turned ON. The rear wiper and washer switch cannot be repaired and, if faulty or damaged, the entire switch unit must be replaced. The switch illumination lamp bulb is available for service replacement.

The rear wiper and washer switch features a detent in the Wipe position, and a momentary Wash position. The bottom of the switch rocker is pushed down to its detent to activate the rear wiper system, and down again to the momentary position to activate the rear washer system. Pushing the top of the switch rocker moves the switch to the OFF position, which also has a detent. When the ignition switch is in the ON position, battery current from a fuse in the Power Distribution Center (PDC) is provided to the rear wiper and washer system fuse in the Junction Block (JB) through a fused ignition switch output (run) circuit. The switch is connected to the vehicle electrical system through a single dedicated take out and connector in the instrument panel wire harness. The intensity of the switch illumination lamp is controlled by the panel lamps dimmer rheostat in the headlamp switch. Refer to the owner's manual in the vehicle glove box for more information on the features, use and operation of the rear wiper and washer switch.