1988 JEEP CHEROKEE tailgate

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DEFO GGER - R EA R W IN DO W

1988 J e ep C hero ke e
1988 Defoggers
REAR WINDOW
Jeep: All Models
DESCRIPTION & OPERATION
System consists of 2 vertical bus bars and horizontal rows of
heating elements fused to inside of glass, a control switch, an
indicator light, and timer relay.
The grid feed wire is connected to bus bar on driver's side
of window. Ground bus bar is on right side of vehicle. Timer/relay
receives current from fuse block. A circuit breaker protects defogger
circuit.
NOTE: On some Jeep models, defogger switch and electric tailgate
switch are serviced as an assembly.
TROUBLE SHOOTING
NOTE: Control switch testing is not available for Wrangler models.
1) On Cherokee, Comanche and Wagoneer models, turn ignition
switch to "ON" position. Check for current at "I" and "B" terminals.
See Fig. 1 . If there is no current, check circuit and repair as
necessary. Make sure that switch has a good ground through wire
connected to "G" terminal.
2) With a good ground circuit and ignition switch in "ON"
position, current should be present at "L" terminal. If there is no
current, replace control switch.
Fig. 1: Jeep Control Switch Terminals
3) On Grand Wagoneer models, turn ignition switch to "ON"
position and press defogger switch. Separate wiring harness at
connector under dash. Connect a 12-volt test light from Purple wire to

1) On Grand Wagoneer models, attach negative lead of
voltmeter to ground. Probe Red wire at relay with voltmeter positive
lead. Battery voltage should be indicated. If no voltage is indicated,
operate tailgate window.
2) If window operates, wire between relay and window switch
is open. Probe Orange wire at relay with voltmeter positive lead. No
voltage should be indicated. Turn ignition switch to "ON" position.
Voltmeter should indicate voltage. If not, relay is defective or not
receiving voltage from Purple wire.
3) If relay operates properly, it should remain energized for
8 to 12 minutes before opening. If time period is too short or too
long, relay is defective. If relay did not energize, connect a jumper
wire to a 12-volt source in tailgate and probe Purple relay terminal.
4) If relay "clicks", trace Purple wire for open or short. If
relay does not click, check relay ground. If ground is okay, relay
should be replaced.

Rear Window Defogger Relay Under instrument panel, to
right of steering column.
Rear Wiper Relay In tailgate, next to wiper
motor.
Starter Relay (Graphic 1) Behind right headlight, on
wheelwell.

Automatic Load Level Compressor In right rear corner of engine
compartment.
Idle Speed Actuator
(ISA) Motor On right side of throttle
body.
Power Door Lock Motor Behind trim panel in door.
Power Window Motor Behind trim panel, in center
of door.
Rear Washer Motor In left front corner of
engine compartment.
Rear Wiper Motor Behind trim panel, in upper
center of tailgate.

PO W ER W IN DO W S

1988 J e ep C hero ke e
1988 Power Windows
JEEP SIDE & TAILGATE WINDOWS
Cherokee, Comanche, Grand
Wagoneer, Wagoneer
DESCRIPTION
All models have a tape-driven window regulator system in the
side doors, and a mechanical regulator in rear door of Grand Wagoneer.
On Grand Wagoneer, the tailgate window operates on 2 circuits, from an
instrument panel switch or an external key switch at the tailgate.
Side windows are operated by individual switches at each door, or by a
complete set of control switches at the instrument panel or drivers
door. The system is protected by a 30 amp circuit breaker in the fuse
panel.
TESTING
NOTE: Ensure instrument panel tailgate switch is properly grounded
as motor grounds through switch. The electric tailgate and
defogger switch are serviced as an assembly.
INSTRUMENT PANEL TAILGATE SWITCH
Grand Wagoneer
1) Turn ignition on. Using a 12-volt test light, connect one
end of test light to ground and probe Red wire. If test light does not
glow, repair feed circuit.
2) If test light glows, probe Brown wire with switch in "UP"
position. If test light does not glow, replace switch. If test light
glows, move switch to "DOWN" position and probe Tan wire. If test
light does not glow, replace switch. If test light glows, check
tailgate window switch.
TAILGATE WINDOW SWITCH
Grand Wagoneer
1) Using a 12-volt test light, connect one end of test light
to ground and probe Red wire of tailgate window switch. If test light
does not glow, repair feed circuit.
2) If test light glows, probe Tan wire. Turn tailgate switch
to "DOWN" position. If test light does not glow, replace switch. If
test light glows, probe Brown wire. Turn tailgate switch to "UP"
position.
3) If test light does not glow, replace switch. If test light
glows, check tailgate window safety switch.
TAILGATE WINDOW SAFETY SWITCH
Grand Wagoneer
1) Using a 12-volt test light, connect one end of test light
to ground and probe Brown wire of safety switch. Turn tailgate switch
to "UP" position. If test light glows, voltage is present at switch.
If test light does not glow, check feed circuit and repair as
necessary.
2) Probe Brown wire. Turn tailgate switch to "UP" position
and close safety switch. If test light does not glow, replace switch.

If test light glows, check tailgate window motor.
TAILGATE WINDOW MOTOR
Grand Wagoneer
1) Using a 12-volt test light, connect one end of test light
to ground and probe Tan wire at motor. Close safety switch and turn
tailgate window switch to "DOWN" position. If test light glows and
motor does not operate, replace motor. If test light does not glow,
check feed circuit to motor and repair as necessary.
2) Probe Brown wire at motor. Close safety switch and turn
tailgate window switch to "UP" position. If test light glows and motor
does not operate, replace motor. If test light does not glow, check
feed circuit to motor and repair as necessary.
SIDE WINDOW MASTER SWITCH CIRCUIT
1) Remove escutcheon and housing from master switch. Separate
terminal plate by releasing retainer hooks to expose terminal ends.
Turn ignition on.
2) Using a 12-volt test light, connect one lead to Black wire
and other lead to Red terminal. Repeat test at second Black wire. If
test light does not glow in either test, remove lead to Black terminal
and connect to chassis ground.
3) If test light glows, an open exists between master switch
and ground. If test light does not glow, it indicates a defective
circuit breaker or an opening in the Red wire from circuit breaker to
master switch.
SIDE WINDOW CONTROL SWITCH & MOTOR TEST
Grand Wagoneer
1) Connect test light between terminals of Orange and Yellow
wires. Operate control switch up and down. If test light glows in both
switch positions, wires, individual door and master switches are not
defective.
2) Disconnect White and Green motor leads at terminal plate,
and connect to Green and White leads. Operate master switch. If window
goes up and down, motor is okay, but switch is defective. If motor
does not operate, remove trim panel and check connections and leads to
motor. If motor operates, switch is defective.
SIDE WINDOW MOTOR
Connect test battery positive lead to one of the motor
terminals. Connect negative lead to other terminal. Motor should
rotate in one direction to go up or down. Reverse battery leads, motor
should rotate in opposite direction. If window does not move, replace
motor.
SWITCH VOLTAGE TEST
1) Turn ignition on. Remove switch from trim panel.
Disconnect terminal block on wiring harness from switch body. Connect
one lead of test light to Red wire terminal and other end to ground.
2) If test light glows, wiring between battery and switch is
functional. Check continuity in Black wire (ground). If test light
does not glow, check circuit breaker. If okay, check for a broken
wire.
SWITCH UP & SWITCH DOWN TEST

TAILGATE WINDOW REGULATOR & MOTOR
Removal (Grand Wagoneer)
1) Remove carpet (if equipped) and tailgate access cover.
Remove retainers attaching regulator arms to channel. Disengage
regulator arm pins from channel, and raise glass.
2) Carefully support glass in raised position. Disconnect
wiring harness from safety switch. If regulator attaching screws are
covered by sector gears, place a jumper wire between terminals of
safety switch connector.
NOTE: If regulator attaching screws are accessible, remove
regulator attaching screws and regulator.
3) Place key in tailgate switch and operate motor until
regulator attaching screws are accessible. Hold regulator in this
position, and wedge a screw between meshing teeth.
4) Remove regulator attaching screws and regulator. Using a
large screwdriver, release spring tension from tension bracket. Remove
motor attaching screws and motor.
Installation
To install, reverse removal procedure.
SIDE WINDOW MASTER SWITCH
Removal
1) Disconnect battery negative cable. Remove retaining screws
and escutcheon. Remove switch housing screws.
2) Pull switch out to expose wires. Disconnect terminal plate
from switch. Depress retainer clips through holes in switch housing,
and remove switch.
Installation
To install, reverse removal procedure.
FRONT & REAR DOOR REGULATORS & MOTORS
Removal
1) Raise window half way up. Disconnect battery negative
cable. Remove door trim panel and water shield.
2) Insert a drift punch into hole in door inner panel, or use
masking tape to hold window half way up. Remove regulator arm retainer
clip, and remove arm from bottom window channel.
3) Disconnect wires from motor. Remove inner door panel-to-
regulator nuts and bolts. Remove regulator and motor assembly.
Installation
To install, reverse removal procedure.