reset JEEP CHEROKEE 1994 Service Repair Manual

not change except when a spindle or ball stud is
damaged or bent. The angle is not adjustable and the
damaged component(s) must be replaced to correct
mis-alignment.
CAUTION:Do not attempt to modify any suspension
or steering component by heating and bending.
PRE-ALIGNMENT INSPECTION
Before starting a front wheel alignment, the follow-
ing inspection and necessary corrections must be
completed.
(1) Tires with the same recommended air pressure,
size, and thread wear. Refer to Group 22, Tires And
Wheels for diagnosis information.
(2) Front wheel bearings for wear.
(3) Ball studs, steering linkage pivot points and
steering gear for looseness, roughness, binding or
wear. Refer to Group 19, Steering for additional in-
formation.
(4) Front wheels for excessive radial or lateral
runout and unbalance. Refer to Group 22, Tires And
Wheels for diagnosis information.
(5) Suspension components for wear and noise.
Check components for correct torque. Refer to Groups
2 and 3, Suspension and Axle for additional informa-
tion.
ALIGNMENT MEASUREMENTS AND ADJUSTMENTS
Before each alignment reading, the vehicle should
be jounced (rear first, then front). Grasp each bumper
at the center and jounce the vehicle up and down
several times. Always release the bumper in the
down position.Set the front end alignment to
specifications with the vehicle at its NOR-
MALLY RIDE HEIGHT.
CAMBER
The wheel camber angle (Fig. 1) is preset at ZERO
DEGREES (0É). The angle is not adjustable and can-
not be altered.
CASTER
The caster angle (Fig. 1) is set at:
²XJ manual transmission, POSITIVE 6.5 DE-
GREES (+6.5É).
²XJ automatic transmission, POSITIVE 8.0 DE-
GREES (+8.0É).
²YJ all transmissions, POSITIVE 6.0 DEGREES
(+6.0É).
Before checking the caster of the front axle for cor-
rect angle. Be sure the axle is not bent or twisted.
Road test the vehicle, and make left and right
turns. If the steering wheel returns to the center po-
sition unassisted, the caster angle is correct. How-ever, if steering wheel does not return toward the
center position unassisted, an incorrect caster angle
is probable.
Caster can be adjusted by installing the appropri-
ate size shims (Fig. 2, 3).Changing caster angle
will also change the front propeller shaft angle.
The propeller shaft angle has priority over
caster. Refer to Group 16, Propeller Shafts for
additional information.
Fig. 2 AdjustmentÐYJ Vehicles
Fig. 3 AdjustmentÐXJ Vehicles
2 - 6 FRONT SUSPENSION AND AXLEJ

SPEED CONTROLÐPCM OUTPUT
Speed control operation is regulated by the power-
train control module (PCM). The PCM controls the
vacuum to the throttle actuator through the speed
control vacuum and vent solenoids. Refer to Group
8H for speed control information.
TACHOMETERÐPCM OUTPUT
The powertrain control module (PCM) supplies en-
gine rpm values to the instrument cluster tachome-
ter (if equipped). Refer to Group 8E for tachometer
information.
TORQUE CONVERTER CLUTCH RELAYÐPCM
OUTPUT
ALL 2.5L 4 CYL. WITH 3-SPEED AUTO. TRANS
4.0L 6 CYL. YJ MODELS WITH 3-SPEED AUTO.
TRANS
The transmission mounted torque converter clutch
(TCC) solenoid is used to control the torque con-
verter. The solenoid is controlled through the power-
train control module (PCM) and by the TCC relay.
This relay is used only on vehicles equipped with a
3-speed automatic transmission.
An electrical output signal is sent from the PCM to
the TCC relay after the PCM receives information
from the vehicle speed, MAP, throttle position and
engine coolant temperature sensors. After the TCC
relay receives this necessary information, it will send
a signal to the torque converter clutch solenoid to
control the torque converter.
On YJ models the TCC relay is located in the en-
gine compartment, on the cowl panel and near the
battery (Fig. 24). On XJ models the TCC relay is lo-
cated in the power distribution center (PDC) (Fig.
23).
OPEN LOOP/CLOSED LOOP MODES OF
OPERATION
As input signals to the powertrain control module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT). There
are several different modes of operation that deter-
mine how the PCM responds to the various input sig-
nals.
MODES
²Open Loop
²Closed Loop
During Open Loop modes, the powertrain control
module (PCM) receives input signals and responds
only according to preset PCM programming. Input
from the oxygen (O2S) sensor is not monitored dur-
ing Open Loop modes.
During Closed Loop modes, the PCM will monitor
the oxygen (O2S) sensor input. This input indicates
to the PCM whether or not the calculated injector
pulse width results in the ideal air-fuel ratio. This
ratio is 14.7 parts air-to-1 part fuel. By monitoring
the exhaust oxygen content through the O2S sensor,
the PCM can fine tune the injector pulse width. This
is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
²Ignition switch ON
²Engine start-up (crank)
²Engine warm-up
²Idle
²Cruise
²Acceleration
²Deceleration
²Wide open throttle (WOT)
²Ignition switch OFF
The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle
and cruise modes, (with the engine at operating tem-
perature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following ac-
tions occur:
²The powertrain control module (PCM) pre-posi-
tions the idle air control (IAC) motor.
²The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic fuel
strategy.
²The PCM monitors the engine coolant temperature
sensor input. The PCM modifies fuel strategy based
on this input.
Fig. 24 TCC Relay LocationÐYJ Models
JFUEL SYSTEM 14 - 27

ABS BRAKE DIAGNOSIS
INDEX
page page
ABS Fault Diagnosis....................... 4
ABS System Wiring and Electrical Circuits...... 4
ABS Warning Light Display.................. 3
Brake Warning Light Display................. 4
Diagnosis Procedures...................... 3
ECU Diagnosis........................... 4
HCU Diagnosis........................... 4Loss of Sensor Input....................... 3
Operating Sound Levels.................... 3
Rear Speed Sensor Air Gap................. 3
Steering Response........................ 3
Vehicle Response in Antilock Mode............ 3
Wheel/Tire Size and Input Signals............. 3
DIAGNOSIS PROCEDURES
ABS diagnosis involves three basic steps. First is
observation of the warning light display. Second is a
visual examination for low fluid level, leaks, parking
brakes applied, or obvious damage to system compo-
nents or wires. The third step involves using the
DRB II scan tool to identify a faulty component.
The visual examination requires a check of reser-
voir fluid level and all system components. Things to
look for are leaks, loose connections, or obvious com-
ponent damage.
The final diagnosis step involves using the DRB II
scan tool to determine the specific circuit or compo-
nent at fault. The tester is connected to the ABS di-
agnostic connector in the passenger compartment.
The connector is at the driver side of the center con-
sole under the instrument panel. Refer to the DRB II
scan tool Manual for tester procedures. Also refer to
the ABS Fault Diagnosis charts at the end of this
section for additional diagnosis information.
Initial faults should be cleared and the vehicle road
tested to reset any faults that remain in the system.
Faults can be cleared with the DRB II scan tool.
REAR SPEED SENSOR AIR GAP
The front wheel sensors are fixed and cannot be ad-
justed. Only the rear sensor air gap is adjustable. Air
gap must be set with a brass feeler gauge.
Correct air gap is important to proper signal gen-
eration. An air gap that is too large may cause com-
plete loss of sensor input. Or, a gap that is too small
could produce a false input signal, or damaging con-
tact between the sensor and tone ring.
WHEEL/TIRE SIZE AND INPUT SIGNALS
Antilock system operation is dependant on accurate
signals from the wheel speed sensors. Ideally, the ve-
hicle wheels and tires should all be the same size
and type. However, the Jeep ABS system is designed
to function with a compact spare tire installed.
OPERATING SOUND LEVELS
The ABS pump and solenoid valves may produce
some sound as they cycle on and off. This is a normal
condition and should not be mistaken for faulty oper-
ation.
VEHICLE RESPONSE IN ANTILOCK MODE
During antilock braking, the HCU solenoid valves
cycle rapidly in response to ECU inputs.
The driver will experience a pulsing sensation
within the vehicle as the solenoids decrease, hold, or
increase pressure as needed. A pulsing brake pedal
will also be noted.
The pulsing sensation occurs as the solenoids cycle
during antilock mode braking. A slight pulse in the
brake pedal may also be noted during the dynamic
self check part of system initialization.
STEERING RESPONSE
A modest amount of steering input is required dur-
ing extremely high deceleration braking, or when
braking on differing traction surfaces. An example of
differing traction surfaces would be when the left
side wheels are on ice and the right side wheels are
on dry pavement.
LOSS OF SENSOR INPUT
Sensor malfunctions will most likely be due to
loose connections, damaged sensor wires, incorrect
rear sensor air gap, or a malfunctioning sensor. Ad-
ditional causes of sensor faults would be sensor and
tone ring misalignment or damage.
ABS WARNING LIGHT DISPLAY
ABS Light Illuminates At Startup
The amber ABS light illuminates at startup as
part of the system self check feature. The light illu-
minates for 2-3 seconds then goes off as part of the
normal self check routine.
ABS Light Remains On After Startup
An ABS system fault is indicated when the light
remains on after startup. Diagnosis with the DRB II
JBRAKES 5 - 3

CLUTCH
CONTENTS
page page
CLUTCH DIAGNOSIS..................... 3
CLUTCH SERVICE...................... 10GENERAL INFORMATION.................. 1
GENERAL INFORMATION
INDEX
page page
Clutch Component Lubrication................ 1
Clutch Components........................ 1Clutch Linkage Fluid....................... 1
Clutch Operation.......................... 2
CLUTCH COMPONENTS
MECHANICAL COMPONENTS
The clutch mechanism in XJ/YJ models with man-
ual transmission consists of a single, dry-type clutch
disc and a diaphragm style clutch cover. A hydraulic
linkage is used to operate the clutch disc and cover.
The transmission input shaft is supported in the
crankshaft by a bearing. A sleeve type release bear-
ing is used to engage and disengage the clutch cover
pressure plate.
The release bearing is operated by a release fork in
the clutch housing. The fork pivots on a ball stud
mounted inside the housing. The release fork is actu-
ated by a hydraulic slave cylinder mounted in the
housing. The slave cylinder is operated by a clutch
master cylinder mounted on the dash panel. The cyl-
inder push rod is connected to the clutch pedal.
The clutch disc has cushion springs in the disc hub.
The clutch disc facing is riveted to the hub. The fac-
ing is made from a non-asbestos material. The clutch
cover pressure plate is a diaphragm type with a one-
piece spring and multiple release fingers. The pres-
sure plate release fingers are preset during
manufacture and are not adjustable.
HYDRAULIC LINKAGE COMPONENTS
The hydraulic linkage consists of a clutch master
cylinder with integral reservoir, a clutch slave cylin-
der and an interconnecting fluid line.
The clutch master cylinder push rod is connected to
the clutch pedal. The slave cylinder push rod is con-
nected to the clutch release fork. The master cylinder
is mounted on the driver side of the dash panel ad-jacent to the brake master cylinder and booster as-
sembly. This positioning is similar for both left and
right hand drive models.
CLUTCH LINKAGE FLUID
The integral clutch master cylinder reservoir, slave
cylinder and fluid lines are prefilled with fluid prior
to assembly operations.
The hydraulic system should not require additional
fluid under normal circumstances. In fact,the reser-
voir fluid level will actually increase as normal
clutch wear occurs. For this reason, it is impor-
tant to avoid overfilling, or removing fluid from
the reservoir.
If inspection or diagnosis indicates additional fluid
may be needed, use Mopar brake fluid, or an equiv-
alent meeting standards SAE J1703 and DOT 3. Do
not use any other type of fluid.
CLUTCH COMPONENT LUBRICATION
Proper clutch component lubrication is important
to satisfactory operation. Using the correct lubricant
and not overlubricating are equally important. Apply
recommended lubricant sparingly to avoid disc and
pressure plate contamination.
Clutch and transmission components requiring lu-
brication are:
²pilot bearing
²release lever pivot ball stud
²release lever contact surfaces
²release bearing bore
²clutch disc hub splines
²clutch pedal pivot shaft bore
²clutch pedal bushings
²input shaft splines
JCLUTCH 6 - 1

COMPASS REPAIR PROCEDURES
VARIATION ADJUSTMENT PROCEDURE
Variance is the difference between magnetic North
and geographic North. In some areas the difference
between magnetic and geographic north is great
enough to cause the compass to give false readings. If
this occurs, the variance must be set.
To set the variance:
(1) Turn ignition switch to the ON position.
(2) Depress both buttons and holddown until VAR
light appears. This takes about 5 seconds.
(3) Release both buttons.
(4) Using the map (Fig. 1) find your geographic lo-
cation and note the zone number.
(5) Press the U.S./METRIC button to sequentially
go through the numbers until the zone number for
your area appears in the display.
(6) Press the COMP/TEMP button to enter this
zone number.
(7) Confirm correct directions are indicated.
COMPASS CALIBRATION PROCEDURE
CAUTION: DO NOT use magnetic tools when servic-
ing the overhead console.
CAUTION: DO NOT place any external magnets
such as magnetic roof mount antennas, in the vicin-
ity of the compass.
Do not attempt to set compass near large metal ob-
jects such as other vehicles, large buildings or
bridges. The compass features an ``Auto-Cal'' design
which simplifies the calibration procedure. During
normal driving this feature automatically updates
the compass calibration. This takes into account in-
cremental changes in magnetism the vehicle may see
over its lifetime.
Whenever the compass is calibrated manually,
the variation number must also be reset.
Calibrate the compass as follows:
(1) Start the engine.
(2) Depress both buttons on the compass and hold
down until CAL light appears. This takes about 10
seconds and appears about 5 seconds after the VAR
light appears.
(3) Release buttons.
(4) Drive vehicle on a level surface that is away
from metal objects through three or more complete
Fig. 1 Variance Settings
Chart 3
8C - 4 OVERHEAD CONSOLEJ

circles, in not less than 48 seconds. The CAL light
will go off and the compass is now calibrated.
(5) Reset variation number. This step must be
done every time step 2 is performed.
If CAL light does not go off, either there is ex-
cessive magnetism near the compass or the unit
is defective. Repeat the degaussing and calibra-
tion procedures at least one more time.
If the wrong direction is still indicated, the
area selected may be too close to a magnetic
source. Repeat the calibration procedure in an-
other location.
DEGAUSSING PROCEDURE
The tool used to degauss or demagnetize the forward
console attaching screw and roof panel is the Miller
Tool 6029. Equivalent units must be rated as continu-
ous duty for 110/115 volts, 60Hz with a field strength of
over 350 gauss at 1/4 inch beyond the tip of the probe.
In this degaussing procedure the degaussing tool is
used to demagnetize both the roof panel and console
forward mounting screw.
(1) Be sure the ignition switch is in the OFF posi-
tion before you begin the degaussing procedures.
CAUTION: Keep the degaussing tool at least 2 inches
away from the compass area when plugging it in.
(2) Plug the degaussing tool into a standard
110/115 volt AC outlet.
CONSOLE FORWARD MOUNTING SCREW
(3) Slowly approach the head of the forward
mounting screw with the plastic coated tip of the de-
gaussing tool. Contact the head of the screw for
about two seconds.
(4) With the degaussing tool still energized, slowly
back it away from the screw until the tool is at least
2 inches from the screw head then unplug the tool.
ROOF PANEL
(5) Place an 8 1/2 X 11 piece of paper on the center
of the roof at the windshield, oriented lengthwise
from front to rear. The purpose of the paper is pro-
tect the roof panel from scratches and define the area
to be degaussed (Fig. 2). Figure 2 shows the recom-
mended sweep pattern of 1/2 inch between passes in
a sweeping zig-zag pattern.
(6) Plug in the degaussing tool. Keep the tool at
least 2 inches away from the compass unit.
(7) Slowly approach the center of the roof panel at
the windshield with the degaussing tool plugged in.
(8) Contact the roof panel with the tip of the tool
(be sure template is in place to avoid scratching the
roof panel). Using slow sweeping motions of 1/2 inch
between sweeps, move the tool approximately 49ei-
ther side of the centerline and at least 11 inches
back from the windshield.(9) With the degaussing tool still energized, slowly
back it away from the roof panel until the tip is at
least 2 inches from the roof then unplug the tool.
(10) Calibrate the compass and set the variance as
described.
SELF-DIAGNOSTIC TEST
The self-diagnostic test is used to verify the com-
pass is working properly electrically. This can be
used to confirm that the display and all of its seg-
ments are operating properly. Initiate the self-diag-
nostic test as follows:
(1) With the ignition switch in the OFF position si-
multaneously press and hold the COMP/TEMP but-
ton and the US/METRIC button.
(2) Turn ignition switch to ON.
(3) Continue to hold both buttons until the display
performs a walking segment test. In this test all of
the compass points are displayed along with various
number combinations. These combinations verify
that all segments work. To repeat the test, press the
COMP/TEMP button.
(4) Press the US/METRIC button, and all segments
will light simultaneously for about 2 seconds. To re-
peat the test, press the COMP/TEMP button.
(5) Press the US/METRIC button to return to nor-
mal operation.
Fig. 2 Roof Degaussing Pattern
JOVERHEAD CONSOLE 8C - 5

other side. When coolant temperature is too high the
switch closes providing a path to ground, and the indi-
cator bulb lights.
TACHOMETER
The tachometer displays the engine speed (RPM).
With the engine running, the tachometer receives an
engine speed signal from the Powertrain Control
Module pin 43 (values shown in Specifications chart).
SPEEDOMETER/ODOMETER SYSTEM
The speedometer/odometer system consists of an elec-
tric speedometer and pushbutton reset odometer
mounted in the cluster. The system also includes the
wire harness from the cluster to the vehicle speed sen-
sor at the transmission, and the adapter and pinion in
the transmission. A signal is sent from a transmission
mounted vehicle speed sensor to the speedometer/odom-
eter circuitry through the wiring harness. Refer to
Group 21 - Transmission for selecting the proper pinion,
and selecting and indexing the proper adapter.
FUEL GAUGE
The fuel gauge pointer position is controlled by a
magnetic field created by electrical current flow through
the coils within the gauge. A change in current flow will
change the magnetic field which changes the pointer po-
sition. The fuel level sender is a variable resistor that
changes electrical resistance with a change of the level
of fuel in the tank (values shown in Specifications
chart).
LOW FUEL WARNING LAMP
The low fuel warning lamp will light when the fuel
level falls below approximately 4 gallons. A low fuel
warning module controls when the lamp will light.
When the module senses 66.5 ohms or less from the
fuel level sender for 10 continuous seconds, the lamp
will light. The lamp will remain on until the module
senses 63.5 ohms or more from the fuel level sender
for 20 continuous seconds.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have an
optional upshift indicator lamp. The lamp is controlled
by the Powertrain Control Module. The lamp lights to
indicate when the driver should shift to the next high-
est gear for best fuel economy. The Powertrain Control
Module will turn the lamp off after 3 to 5 seconds if the
upshift is not performed. The lamp will remain off until
the vehicle stops accelerating and is brought back to the
range of lamp operation or shifted into another gear.
The indicator lamp is normally illuminated when
the ignition switch is turned ON and is turned off
when the engine is started. The lamp will be lighted
during engine operation according to engine speed
and load.
BRAKE INDICATOR LAMP
The brake indicator lamp warns the driver that the
parking brake is applied or that hydraulic pressure in
the split brake system is unequal.
Voltage is supplied through the brake indicator
bulb to 3 switches. A path to ground for the current
is available if:
²The brake warning switch is closed (with unequal
brake system hydraulic pressures), or
²
The ignition switch is in the START position (to test
the bulb), or
²The park brake switch is closed (with the parking
brake applied).
ANTI-LOCK BRAKE SYSTEM (ABS) INDICATOR
LAMP
The anti-lock brake system (ABS) lamp lights to in-
dicate a system self-check is in process at vehicle
start-up. If light remains on after start-up or comes
on and stays on while driving, it may indicate that
the ABS system has detected a malfunction or has
become inoperative.
4WD INDICATOR LAMP
COMMAND-TRAC 4WD
The PART TIME lamp lights when the vehicle is en-
gaged in four-wheel drive mode. Voltage is supplied to
one side of the indicator bulb. A switch in the transfer
case area is connected to the other side of the indicator
bulb. When the switch is closed, a path to ground is pro-
vided and the indicator bulb lights.
SELECT-TRAC 4WD
The four-wheel drive icon or FULL TIME lamp
lights when the vehicle is engaged in full time four-
wheel drive mode. The PART TIME lamp lights when
the vehicle is in part time four-wheel drive mode.
Voltage is supplied to one side of the indicators.
Switches in the transfer case area are connected to
the other side of the indicator bulbs. When a switch
is closed, a path to ground is provided and the indi-
cator bulb lights.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE)
The Malfunction Indicator Lamp (Check Engine)
lights each time the ignition switch is turned ON and
stays on for 3 seconds as a bulb test.
If the PCM receives an incorrect signal or no signal
from certain sensors or emission related systems the
lamp is turned on (pin 32 of PCM). This is a warning
that the PCM has recorded a system or sensor mal-
function. In some cases when a diagnostic trouble
code is declared the PCM will go into a limp-in mode
in an attempt to keep the system operating. It sig-
nals an immediate need for service.
The lamp also can be used to display diagnostic
trouble codes (DTC). Cycle the ignition switch ON,
OFF, ON, OFF, ON within 5 seconds. This will allow
any trouble codes stored in the PCM memory to be
displayed in a series of flashes representing digits.
8E - 2 XJ INSTRUMENT PANEL AND GAUGESJ

INSTRUMENT PANEL AND GAUGESÐYJE
CONTENTS
page page
GAUGE PACKAGE DIAGNOSIS............ 22
GAUGE PACKAGE GENERAL INFORMATION . 22
GAUGE PACKAGE SERVICE PROCEDURES . . 24
INSTRUMENT CLUSTER DIAGNOSIS....... 14INSTRUMENT CLUSTER GENERAL INFORMATION.14
INSTRUMENT CLUSTER SERVICE PROCEDURES.. 17
SPECIFICATIONS....................... 27
INSTRUMENT CLUSTER GENERAL INFORMATION
SPEEDOMETER/ODOMETER SYSTEM
The speedometer/odometer system consists of an
electric speedometer and pushbutton reset odometer
mounted in the cluster. The system also includes the
wire harness from the cluster to the vehicle speed
sensor at the transmission, and the adapter and pin-
ion in the transmission. A signal is sent from a
transmission mounted vehicle speed sensor to the
speedometer/odometer circuitry through the wiring
harness. Refer to Group 21 - Transmission for select-
ing the proper pinion, and selecting and indexing the
proper adapter.
TACHOMETER
The tachometer displays the engine speed (RPM).
With the engine running, the tachometer receives anengine speed signal from the Powertrain Control
Module pin 43 (values shown in Specifications chart).
INDICATOR LAMPS
The Brake, Upshift (2.5L with 5 speed transmis-
sion except California), and Malfunction Indicator
(Check Engine) lamps are located in the indicator
lamp panel above the steering column. The lamps
share a common battery feed connection through the
ignition switch and fuse #9.
The turn signals, high beam indicator, seat belt re-
minder, hazard lamp, master lighting and illumina-
tion bulbs are supplied battery voltage through
various switches and share a common ground.
INSTRUMENT CLUSTER DIAGNOSIS
INDEX
page page
Brake Indicator Lamp...................... 16
DiagnosingÐAll Lamps Out................. 16
Instrument Panel Illumination Lamps.......... 16
Malfunction Indicator Lamp (Check Engine)..... 16Seat Belt Reminder Lamp................... 16
Speedometer............................ 14
Tachometer............................. 14
Upshift Indicator Lamp..................... 16
SPEEDOMETER
(1) Raise vehicle.
(2) Disconnect the vehicle speed sensor connector.
(3) Connect a voltmeter between the black wire
pin of the connector and ground.
(4) Turn the ignition switch to the ON position.
(5) Check for approximately 5 volts. If OK, per-
form vehicle speed sensor test. Refer to the appropri-
ate Powertrain Diagnostic Procedures manual. If not
OK, continue with step 6.
(6) Turn ignition switch to OFF position.(7) Check continuity between vehicle speed sensor
connector and terminal 13 of instrument cluster con-
nector. If OK, replace speedometer. If not OK, repair
open circuit.
TACHOMETER
(1) Tachometer input is from the Powertrain Con-
trol Module (PCM) pin 43. Use the DRB scan tool to
perform actuator test. If OK, continue with step 2. If
not, replace PCM.
(2) Check for continuity between cluster connector
pin 12 and PCM pin 43. If OK, replace tachometer. If
not, repair open circuit.
8E - 14 YJ INSTRUMENT PANEL AND GAUGESJ

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