1994 JEEP CHEROKEE fuse

REAR WINDOW DEFOGGER
CONTENTS
page page
GENERAL.............................. 1
XJ .................................... 4YJ .................................... 4
GENERAL
INDEX
page page
Diagnosis............................... 2
Rear Window Defogger Grid Repair........... 2Rear Window Defogger Grid Test............. 1
Switch Testing............................ 2
Using heating elements bonded to the rear window
glass, the rear defogger will clear condensation, frost
and light snow coverings from the rear window.
The horizontal grid lines and vertical bus bar lines,
printed and baked on inside surface of the rear win-
dow glass, comprise an electrical circuit. The electri-
cally conductive lines are composed of a silver-
ceramic material which when baked on glass
becomes bonded to the glass and is highly resistant
to abrasion.
The electrical current required to produce the heat
in the grid is supplied through a relay and driver op-
erated switch. When the switch is momentarily de-
pressed, the relay senses a voltage change. This
voltage change causes the relay to change state and
complete a circuit to energize the relay. Once the re-
lay energizes, the contacts close connecting the grid
to battery power.
On the XJ, the power circuit to the grid is pro-
tected by the 25 amp, #18 fuse in the fuse box.
Power for fuse #18 comes from the power distribu-
tion center, fuse #F10. Power for the relay is pro-
tected by the 20 amp, #8 fuse located in the fuse box.
On the YJ, the grid is protected by a 25 amp #6
fuse, located in the fuse box. Power for the relay is
protected by 15 amp #9 fuse, located in the fuse box.
To defog the rear window, momentarily depress the
rocker switch. A light on the rocker switch will illu-
minate indicating that the defogger is operating.
If the ignition switch is ON the first activation of
the defog/defrost feature will last for 10 minutes.
Succeeding activations will last for 5 minutes unless
the ignition switch is turned OFF; then it will recy-
cle back to 10 minutes for the first activation.To stop defogger operation, momentarily push the
switch a second time.
CAUTION: Use care when washing the inside of the
rear window to prevent damage to the defogger
heating elements. Use a soft cloth and a mild wash-
ing solution. Wiping motions should be parallel to
the heating elements. Also, keep all objects a safe
distance from the window to prevent damaging the
heating elements.
REAR WINDOW DEFOGGER GRID TEST
It is possible, that a break may exist or occur in an
individual grid line resulting in no current flow
through the line. When a grid has an open circuit,
the area of glass normally cleared by that grid re-
mains fogged or iced unless, and until it is cleared by
the adjacent grids.
With the engine running at idle, push the rear
window defogger switch to the ON position and re-
lease. The pilot lamp in the rocker switch should
light, indicating defogger operation.
Using a 12-volt DC voltmeter, contact the positive
lead to the feed side vertical bus element on the in-
side surface of the glass. Contact the negative lead to
the ground side bus element. Meter should read be-
tween 11 and 13 volts. Connect the negative lead of
the voltmeter to a good ground; the meter reading
should be constant.
Keep the negative lead connected to ground. Use
the positive lead and carefully contact each grid at
the approximate centerline of the window.
JREAR WINDOW DEFOGGER 8N - 1

A voltage drop of one-half the full amount, approx-
imately 6 volts, indicates a good grid or closed cir-
cuit.
A voltage drop of 12 volts at the centerline indi-
cates a break in the grid between the positive volt-
meter lead and the ground.
No voltage drop (0 volts) at the centerline indicates
a break in the grid between the centerline and the
voltage source or lead.
The exact location of the break can be pinpointed
by moving positive voltmeter lead to the left or right
along grid. An abrupt change in the voltage reading
will be noticed. The break is at that point in the
grid.
REAR WINDOW DEFOGGER GRID REPAIR
Locate the broken or open grid.
Use the grid repair kit (available as a service part)
by using the following procedure:
(1) Mark the location of the broken or open grid on
the exterior surface of the glass using a suitable
marking pencil.
(2) Lightly rub the area to be repaired (inside the
rear window) using fine steel wool. Clean the area
with alcohol.
(3) Attach two strips of masking tape to the inside
surface of the rear window (above and below the
break in the grid) (Fig. 1).
(4) Remove package separator clamp and mix plas-
tic conductive epoxy thoroughly. Fold in half and cut
center corner to dispense epoxy.
(5) Apply conductive epoxy through slit in mask-
ing tape. Overlap both ends of the break.
(6) For a terminal or pigtail replacement, mask ad-
jacent areas so epoxy can be extended onto line and
buss bar. Apply a thin layer of epoxy to area where
terminal was fastened and to adjacent line.
(7) Apply a thin layer of conductive epoxy on ter-
minal and place terminal on desired location. To pre-
vent terminal from moving while the epoxy is curing,
it must be wedged or clamped.
(8) Carefully remove masking tape from grid line.
(9) Allow epoxy to cure 24 hours at room tempera-ture or use heat gun with a 260É-371ÉC (500É-700ÉF)
range for 15 minutes. Hold gun approximately
254mm (10 inches) from repaired area.
(10) After conductive epoxy is properly cured re-
move wedge from terminal and check out operation
of rear window defogger. Do not attach connectors
until curing is complete.
WARNING: REPAIR KIT MAY CAUSE SKIN OR EYE
IRRITATION.
CONTAINS EPOXY RESIN AND AMINE TYPE
HARDENER, HARMFUL IF SWALLOWED. AVOID
CONTACT WITH SKIN AND EYES. FOR SKIN,
WASH AFFECTED AREAS WITH SOAP AND WA-
TER. DO NOT TAKE INTERNALLY. IF TAKEN
INTERNALLY, INDUCE VOMITING; CALL A
PHYSICIAN IMMEDIATELY. IF IN CONTACT
WITH EYES, FLUSH WITH PLENTY OF WATER.
USE WITH ADEQUATE VENTILATION. DO NOT
USE NEAR FIRE OR FLAME. CONTENTS CON-
TAIN 3% FLAMMABLE SOLVENTS.
WARNING: KEEP OUT OF REACH OF CHIL-
DREN.
SWITCH TESTING
DIAGNOSIS
Refer to Group 8W - Wiring Diagrams for a com-
plete circuit diagram.
BATTERY, IGNITION & FUSES
²Check fuses #6 and #9 (YJ), or #8 and #18 fuse
(XJ). Replace as required.
²If the fuses are not blown check the battery side of
#18 fuse (XJ) or fuse #6 (YJ) for battery voltage. If
battery voltage is not present replace the Maxi fuse
located in the power distribution center.
²Check the ignition side of fuse #9 (YJ), fuse #8
(XJ) for battery voltage. If battery voltage is not
present check for an open from the ignition switch.
DEFOGGER SWITCH
Defogger switch connector separated from de-
fogger switch; turn ignition switch to ON for
voltage tests; turn ignition switch to OFF for re-
sistance tests
²Measure voltage at defogger switch connector ter-
minal D. The meter should read approximately 5
volts momentarily. If not, repair open from relay.
²Refer to switch diagram for resistance tests. If val-
ues do not match, replace defogger switch.
DEFOGGER RELAY
Defogger relay connector separated from de-
fogger relay; turn ignition switch to ON for volt-
age tests; turn ignition switch to OFF for
resistance tests
Fig. 1 Grid Line Repair (Typical)
8N - 2 REAR WINDOW DEFOGGERJ

²Measure voltage at relay connector terminal 4.
The meter should read battery voltage. If not, repair
open to fuse #18 (XJ), or fuse #9 (YJ).
²Measure voltage at relay connector terminal 5.
The meter should read battery voltage. If not, repair
open from #8 fuse XJ, or fuse #6 YJ.
²Measure resistance between relay connector termi-
nal 1 and left side (driver's side) of defogger grid.
The meter should read zero ohms. If not, repair open
between relay connector and left side of defogger
grid.
²Measure resistance between relay connector termi-
nal 2 and a clean chassis ground. The meter should
read zero ohms. If not, repair open between relay
connector and ground.
²Connect relay connector and measure voltage at
terminal 3. The meter should read approximately 5volts. If not, replace defogger relay.
INDICATOR LAMP
Refer to switch diagram for resistance tests. If val-
ues do not match, replace defogger switch.
DEFOGGER GRID
Turn defogger switch to ON; turn ignition
switch to ON for voltage tests; turn ignition
switch to OFF for resistance tests
²Measure voltage at left side (driver's side) of defog-
ger grid. The meter should read battery voltage. If
not, repair open from defogger relay.
²Measure resistance for right side of defogger grid
to a clean chassis ground. The meter should read
zero ohms. If not, repair open between right side of
defogger grid and ground.
JREAR WINDOW DEFOGGER 8N - 3

POWER DOOR LOCKS
CONTENTS
page page
KEYLESS ENTRY........................ 8POWER LOCKS......................... 1
POWER LOCKS
INDEX
page page
Actuator Motor Stall Test.................... 6
Description.............................. 1
Diagnosing Power Door Locks............... 1
General................................. 1Liftgate Lock Cylinder Replacement............ 7
Solenoid and Latch Assembly Replacement..... 6
Switch Replacement....................... 6
GENERAL
The door lock actuators, including liftgate, are con-
trolled by two-way switches. To lock the doors, push
down on either switch. To unlock doors from inside
the vehicle push upward on either switch.
The power door locks do not lock or unlock the
doors from outside the vehicle. Insert the key into
the lock cylinder to lock or unlock each individual
door.
DESCRIPTION
The door locks are operated by reversible motors
that receive voltage from fuse #13 in the fuse panel.
Voltage is applied to the driver's side door lock
switch and the passenger's side door lock switch
through the #9 fuse. With the driver's side door lock
switch in LOCK, voltage is applied through the
switch to the door lock relay coil. The relay coil is
energized which closes the circuit from the circuit
breaker to the lock motor. The motor is grounded by
the unlock relay.
The passenger's side door lock window switch oper-
ates the same as the driver's door switch. The volt-
age and ground paths are reversed to unlock the
doors.
The power door lock operates with battery power
and, therefore, is independent of the ignition switch.
DIAGNOSING POWER DOOR LOCKS
If vehicle has Keyless Entry and the door locks op-
erate properly using door switches but do not work
with transmitter, refer to Keyless Entry in this
group.
NO DOOR LOCKS OPERATE USING DOOR
LOCK SWITCHES
(1) Inspect fuse #13. Replace if necessary. If OK,
measure voltage at battery side of fuse. There should
be 12 volts. If not, repair open from Power Distribu-
tion Center.
(2) Remove door switch and measure voltage at
terminal 1. Meter should read battery voltage. If not,
repair open to #9 fuse.
(3) The power window relays are in the relay cen-
ter. The relay center is located on the lower instru-
ment panel trim cover just right of the steering
column (Fig. 1). Remove both relays.
(4) Measure resistance between lock and unlock re-
lay terminal 4 (87A) and ground. Meter should read
zero ohms. If not, repair open to ground.
(5) Measure voltage at terminal 5 (87) of both the
lock and unlock relays. Meter should read battery
voltage. If OK, next step. If not, repair open to cir-
cuit breaker.
(6) Measure resistance at terminal 2 (85) of both
the lock and unlock relays. Meter should read zero
ohms. If not, repair open to ground.
(7) Hold driver's side switch in LOCK position.
Measure voltage at lock relay terminal 1 (86). Meter
should read battery voltage. If OK, next step. If not,
repair open to driver's side switch.
(8) Hold driver's side switch in UNLOCK position.
Measure voltage at unlock relay terminal 1 (86).
Meter should read battery voltage. If OK, next step.
If not, repair open to driver's side switch.
JPOWER DOOR LOCKS 8P - 1

code received matches the code in the receiver memory
circuit, the receiver triggers the door lock/unlock relays.
The relays complete the circuit to the electric door lock
solenoid to either lock or unlock the doors.
SYSTEM OPERATION
To activate the system, aim the transmitter diode
toward the receiver and press the transmitter signal
button to lock or unlock the doors as desired.
Effective transmitter range is 4.75 meters (15 ft.)
with the transmitter positioned no more than 45 de-
grees from the receiver centerline.
For complete circuit diagrams refer to Group
8W - Wiring Diagrams.
TRANSMITTER PROGRAMMING
Up to 4 Transmitter Identification Codes (TIC's) can
be programed into the receiver at any given time.
(1) Open the driver's door of the vehicle. Leave it
open through the programming procedure.
(2) Move the mechanical door lock lever to the
LOCK position.
(3) Turn the ignition switch to the ON position.
(4) Within 20 seconds, aim a transmitter at the re-
ceiver dome and press the LOCK button for at least
5 seconds. Once the receiver accepts the program-
ming code, the driver's door will unlock.
(5) Once the first transmitter has been pro-
grammed, additional transmitters (up to 4) may be
programmed into the receiver. Within 20 seconds of
the previous transmitter programming, move the me-
chanical door lock lever to the LOCK position. Aimanother transmitter at the receiver dome and press
the LOCK button for at least 5 seconds. The door
lock will cycle again.
(6) To lock the programmed codes into the re-
ceiver, the ignition switch must be turned OFF and
back ON within 20 seconds after programming the
last transmitter's code. At that time, all previous
codes are erased from the module.
DIAGNOSING POWER DOOR LOCKS
NO DOOR LOCKS OPERATE, USING
TRANSMITTER
(1) Measure resistance at keyless entry module
terminal 10. Meter should read zero ohms. If not, re-
pair open to ground.
(2) Measure voltage at keyless entry module termi-
nal 1. Meter should read battery voltage.Battery
voltage must be at least 9 volts for this system to
operate.If not, repair open to #9 fuse.
(3) Jumper test leads keyless entry module termi-
nal 1 to terminal 3. Doors should lock. If OK, replace
module. If not, repair open from terminal 3 to lock
relay terminal 1.
(4) Jumper test leads keyless entry module termi-
nal 1 to terminal 4. Door should unlock. If OK, re-
place module. If not, repair open from terminal 4 to
unlock relay terminal 1.
TRANSMITTER SERVICE
If the receiver malfunctions, only the receiver will
have to be replaced. The new receiver will have to be
reprogrammed. If a transmitter is lost, replace the
transmitter and reprogram the receiver.
Batteries may not be supplied with some re-
placement transmitters. Be sure to check a re-
placement transmitter before attempting to
activate the system.
TRANSMITTER BATTERY REPLACEMENT
(1) Separate transmitter at middle seam (Fig. 2).
Fig. 2 Separate Transmitter Halves
Fig. 1 Keyless Entry Transmitter
JPOWER DOOR LOCKS 8P - 9

POWER SEATS
CONTENTS
page page
DIAGNOSIS............................. 1
GENERAL.............................. 1POWER SEAT MOTOR REPLACEMENT....... 2
SWITCH TESTING....................... 2
GENERAL
The power seat can be adjusted in 6 different direc-
tions (Fig. 1). The control switch is on the lower out-
board side of the seat.
The front lever on the switch raises or lowers (tilts)
the front of the seat cushion. The center lever raises
or lowers the complete seat by moving the switch up
or down. The center lever also moves the seat for-
ward or rearward by moving the switch forward or
rearward. The rear lever raises or lowers (tilts) the
back of the seat cushion.
There are 3 reversible motors that operate the
power seat. The front and rear of the seat are oper-
ated by different motors. They can be raised or low-
ered independently of each other. Moving the center
position seat switch to either the UP or DOWN posi-
tion, runs both the front and rear motors at the same
time.
The forward-rearward motor is operated by the
center position seat switch. When the switch is held
in the FORWARD position, battery voltage is applied
through the switch contacts to pin S3 and the for-ward-rearward motor. The motor is grounded
through pin S4 and the contacts of the back switch to
pin 2 and to ground. The motor runs to drive the seat
forward until the switch is released.
With the switch in the REAR position, pin S4 re-
ceives battery voltage and pin S3 is grounded. This
reversed polarity causes the motor to run in the op-
posite direction and drive the seat backward.
The front motor works in a similar way when the
front height switch is operated.
To raise the entire seat, the center position seat
switch is held in the UP position. This applies bat-
tery voltage to both pins S1 and S5 and the front and
rear motors. Pins S2 and S6 are grounded through
the down switches and the lower switch. Both motors
run to drive the entire seat up. A similar action oc-
curs to move the entire seat down.
Each motor contains a self-resetting circuit breaker
to protect it from overload. Consecutive or frequent
resetting must not be allowed to continue. Make nec-
essary repairs.
DIAGNOSIS
Refer to Group 8W-Wiring Diagrams for a complete
circuit diagram.
Before any testing is attempted the battery should
be fully charged and all connections and pins cleaned
and tightened to insure proper continuity and
grounds.
With the dome light on, apply switch in direction
of the failure. If the dome light dims, the seat may
be jamming. Check for binding. If the dome light
does not dim, then proceed with the following electri-
cal tests.
SEAT MOTOR ASSEMBLY
²Position seat switch to move all 3 seat motors. The
seat should move in all directions. If not, go to No
Seat Motors Operate. If one or more motors operate,
refer to switch testing.
Test seat switch. If OK, replace defective motor.
NO SEAT MOTORS OPERATE
Circuit breaker installed.
²Probe 30 amp circuit breaker, cavity #16 on fuse
panel. If battery voltage is present, replace circuit
breaker.
Fig. 1 Power Seat Switch
JPOWER SEATS 8R - 1

POWER WINDOWS
CONTENTS
page page
DESCRIPTION........................... 1
DIAGNOSIS (Figs. 1 and 2)............... 1SWITCH TESTING....................... 5
WINDOW REGULATOR REPLACEMENT...... 9
DESCRIPTION
All XJ vehicles, equipped with power windows,
have a cable driven window regulator system. A per-
manent magnet motor moves each power window.
Each motor raises or lowers the glass when voltage
is supplied to the motor. The direction the motor
turns depends on the polarity of the supply voltage.
The control switches control the supply voltage polar-
ity.
With the ignition switch in the ON position voltage
from the 60 amp fuse in the Power Distribution Cen-
ter is applied through the power window circuit
breaker. Power then goes to the master switch termi-
nal BY and to the passenger's window switches.
When the driver's window switch is moved UP, the
contacts close a current path to:
²terminal DV
²driver's side front window motor
²terminal CV
²the DOWN contact of the driver's side front win-
dow to ground.
The motor then moves the glass up.
Current flows in a similar way when the UP con-
tact in one of the passenger's window switches is
closed. Current flow through the passenger's window
motors must go through the driver's and the passen-
ger's window switches before it reaches ground.
Each motor is protected by a built-in circuit
breaker. If a window switch is held on too long with
the window obstructed or after the window is fully
up or down, the circuit breaker opens the circuit. The
circuit breaker resets automatically as it cools. Do
not allow frequent or consecutive resetting of the cir-
cuit breaker to continue.
DIAGNOSIS (Figs. 1 and 2)
For information concerning wiring or connectors,
refer to Group 8W - Wiring Diagrams.
NO WINDOWS OPERATE
²Measure voltage at power window feed connector
at fuse panel. Meter should read battery voltage. If
not, replace 60 amp fuse in Power Distribution Cen-
ter.
²Turn ignition switch to OFF and measure resis-
tance from side of cigar lighter socket to ground.
Meter should read zero ohms. If not, repair open to
ground.
²Remove master door lock/power window switch as-
sembly mounting screws. Measure resistance at BLK
wire (terminal DX) at driver's side switch. Meter
should read zero ohms. If not, repair open to ground
splice of instrument panel harness.
²Turn ignition switch to ON and measure voltage
at terminal BY at driver's side switch. Meter should
read battery voltage. If not, repair open to circuit
breaker.
²Operate window switch. If the windows move up
and down go to Switch Testing.
²Perform Switch Test Driver's Door. If switch
passes test, replace defective motors.
ONE WINDOW OPERATES
Remove door panel of inoperative window,
probe harness side of unplugged motor connec-
tor.
²Measure voltage at terminal A of connector, hold-
ing switch in the DOWN position. Meter should read
battery voltage. If not, repair open back to master
switch. If additional switch is in circuit (not driver's
side motor), refer to Switch Testing.
²Measure resistance at terminal B of connector,
holding switch in the DOWN position. Meter should
read zero ohms. Caution, maintain DOWN position
while meter lead is attached. If not, repair open back
to master switch. If additional switch is in circuit
(not driver's side motor), refer to Switch Testing. If
both tests are OK, replace regulator.
JPOWER WINDOWS 8S - 1

POWER MIRRORS
CONTENTS
page page
DIAGNOSIS............................. 1
GENERAL.............................. 1
POWER MIRROR REPLACEMENT........... 4POWER MIRROR SWITCH REPLACEMENT . . . 4
POWER MIRROR SWITCH TESTING......... 2
GENERAL
For information concerning wiring or connectors,
refer to Group 8W - Wiring Diagrams.
The mirror control switch contains two separate
switches, the operating switch and the selector
switch.
Each mirror has two reversible motors: one to ad-
just the mirror view up and down, the other to adjust
the mirror view right and left. The driver operates
three switches that control the polarity of the voltage
to the motors. The mirror select switch directs these
control voltages to either the right or left mirror.
The mirror select switch must be set to L or R to
direct current flow. If the mirror select switch is set
on R and the up-down switch is moved to the UP po-
sition, the voltage path is:
²through the U contact of switch 1
²to pin E
²to the up-down motor in the right mirror.
The ground path is:
²through pin D
²through the mirror select switch contacts
²to the U contacts of switch 3 and switch 2
²to pin F
²to ground.
The right motor runs and tilts the mirror up.
If the switch is pushed to the DOWN position, thesame motor receives voltage. Now the polarity is re-
versed, with pin E grounded. The motor runs in the
opposite direction.
The right mirror left-right motor operates in a sim-
ilar manner when the control switch is moved to the
L or R positions.
The left mirror works the same way as the right
mirror when mirror select switch is moved to L posi-
tion and control switch is operated.
DIAGNOSIS
For information concerning wiring or connectors,
refer to Group 8W - Wiring Diagrams.
²Open door. Dome lamps should light. If not, check
dome fuse.
Remove switch, unplug switch connector
²Measure resistance at mirror switch connector pin
F. Meter should read zero ohms, If not, repair open to
ground.
²Measure voltage at mirror switch connector pin G.
Meter should read battery voltage. If not, repair open
to dome fuse.
Install a jumper lead from pin E to pin F.
²Connect a jumper lead from pin G to: pin A; pin B;
pin C and then pin D. If the mirror moves, replace
switch. If not, repair open to motor and/or replace
motor.
JPOWER MIRRORS 8T - 1