1995 JEEP XJ Brake lamp

COLD CRANKING TEST
(1) Battery must be fully-charged and load tested
before proceeding. See Battery, in this group.
(2) Connect a suitable volt-ampere tester to the
battery terminals (Fig. 2). Refer to the operating in-
structions provided with the tester being used.
(3) Fully engage parking brake. Place manual
transmission in NEUTRAL, automatic transmission
in PARK.
(4) Verify that all lamps and accessories are OFF.
(5) Unplug Auto Shut-Down (ASD) relay from
Power Distribution Center (PDC) to prevent engine
from starting. Relay location is shown on underside
of PDC cover.
(6) Rotate and hold the ignition switch in the START
position. Note cranking voltage and amperage.
(a) If voltage reads above 9.6 volts and amperage
draw reads above specifications, see Feed Circuit Tests.
(b) If voltage reads 12.5 volts or greater and am-
perage reads below specifications, see Control Cir-
cuit Tests.
A cold engine will increase starter current
and reduce battery voltage.
FEED CIRCUIT TESTS
The starter feed circuit tests (voltage drop method)
will determine if there is excessive resistance in the
high-amperage circuit. When performing these tests,
it is important that the voltmeter be connected prop-
erly. Connect voltmeter leads to the terminals that
the cable connectors or clamps are attached to, not to
the cable connectors or clamps. For example: When
testing between the battery and solenoid, touch the
voltmeter leads to the battery post and the solenoid
threaded stud.
The following operation will require a voltmeter ac-
curate to 1/10 (0.10) volt. Before performing the tests,
be certain the following procedures are accomplished:
²unplug Auto Shut-Down (ASD) relay from Power
Distribution Center (PDC) to prevent engine from
starting²place transmission in NEUTRAL (manual trans-
mission) or PARK (automatic transmission)
²parking brake is applied
²
battery is fully-charged (see Battery, in this group).
(1) Connect positive lead of voltmeter to battery
negative post. Connect negative lead of voltmeter to
battery negative cable clamp (Fig. 3). Rotate and
hold ignition switch in the START position. Observe
voltmeter. If voltage is detected, correct poor contact
between cable clamp and post.
(2) Connect positive lead of voltmeter to battery
positive post. Connect negative lead of voltmeter to
battery positive cable clamp (Fig. 3). Rotate and hold
ignition switch in the START position. Observe volt-
meter. If voltage is detected, correct poor contact be-
tween cable clamp and post.
(3) Connect voltmeter to measure between the bat-
tery positive post and the starter solenoid battery
stud (Fig. 4). Rotate and hold ignition switch in the
START position. Observe voltmeter. If voltage reads
above 0.2 volt, correct poor contact at battery cable to
solenoid connection. Repeat test. If reading is still
above 0.2 volt, replace battery positive cable.
Fig. 2 Volt-Amps Tester Connections (Typical)
Fig. 3 Test Battery Connection Resistance
Fig. 4 Test Battery Positive Cable Resistance
(Typical)
JBATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 13

INSTRUMENT PANEL AND GAUGES
GROUP INDEX
INSTRUMENT PANEL AND GAUGESÐXJ...... 1INSTRUMENT PANEL AND GAUGESÐYJ..... 24
INSTRUMENT PANEL AND GAUGESÐXJ
CONTENTS
page page
DIAGNOSIS............................. 5
GENERAL INFORMATION.................. 1SERVICE PROCEDURES.................. 17
SPECIFICATIONS........................ 23
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
or heater and air conditioning components can be ac-
cessed without complete instrument panel removal. If
necessary, the instrument panel can be rolled-down
and removed from the vehicle as an assembly.
Removal of the instrument cluster bezel allows ac-
cess to the cluster assembly, most switches, the cli-
mate controls, and the radio. Removal of the cluster
assembly allows access to the individual gauges, illu-
mination and indicator lamp bulbs, printed circuits,
and most wiring.
Removal of the lower instrument panel allows ac-
cess to heater and air conditioning components, the
fuseblock module, the relay center, and other wiring
and electrical components. Those models equipped
with a driver's-side airbag restraint have a knee
blocker and reinforcement behind the driver's-side
lower instrument panel.
The instrument panel layout is mirror image for
left-hand and right-hand drive vehicles. In most
cases, the diagnosis and service procedures found in
this group are applicable to either vehicle. Although,most illustrations represent only the typical left-hand
drive version. Exceptions are clearly identified as
Right-Hand Drive (RHD).
INSTRUMENT CLUSTERS
Two basic instrument cluster options are offered on
XJ (Cherokee) models. One is referred to as a low-
line cluster, and the other is referred to as a high-
line cluster. Each cluster is divided into two areas:
the gauge area, and the tell-tale area. Each area is
served by a separate printed circuit and wiring con-
nector. Some variations of each cluster exist due to
optional equipment and regulatory requirements.
The low-line cluster includes the following gauges:
²fuel gauge
²speedometer/odometer.
The low-line cluster includes provisions for the fol-
lowing indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²coolant temperature warning lamp
²four-wheel drive indicator lamps
²generator warning lamp
²headlamp high beam indicator lamp
²low oil pressure warning lamp
²low washer fluid warning lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp
²turn signal indicator lamps
²upshift indicator lamp.
JINSTRUMENT PANEL AND GAUGES 8E - 1

The high-line cluster includes the following gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²speedometer/odometer
²tachometer
²trip odometer
²voltmeter.
The high-line cluster includes provisions for the fol-
lowing indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²four-wheel drive indicator lamps
²headlamp high beam indicator lamp
²low fuel warning lamp
²low washer fluid warning lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp
²turn signal indicator lamps
²upshift indicator lamp.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the in-
strument cluster gauge area printed circuit. With the
ignition switch in the OFF position, voltage is not
supplied to the gauges. A gauge pointer may remain
within the gauge scale after the ignition switch is
OFF. However, the gauges do not accurately indicate
any vehicle condition unless the ignition switch is
ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
The gauge needle moves as the movable permanent
magnet aligns itself to the changing magnetic fields
created around it by the electromagnets.
COOLANT TEMPERATURE GAUGE
The coolant temperature gauge gives an indication
of engine coolant temperature. The coolant tempera-
ture sending unit is a thermistor that changes elec-
trical resistance with changes in engine coolanttemperature. High sending unit resistance causes
low coolant temperature readings. Low resistance
causes high coolant temperature readings.
The gauge will read at the high end of the scale
when the ignition switch is turned to the START po-
sition. This is caused by the bulb test circuit wiring
provision. The same wiring is used for the high-line
cluster with a coolant temperature gauge and the
low-line cluster with a coolant temperature warning
lamp. Sending unit resistance values are shown in a
chart in Specifications.
FUEL GAUGE
The fuel gauge gives an indication of the level of
fuel in the fuel tank. The fuel gauge sending unit has
a float attached to a swing-arm in the fuel tank. The
float moves up or down within the fuel tank as fuel
level changes. As the float moves, an electrical con-
tact on the swing-arm wipes across a resistor coil,
which changes sending unit resistance. High sending
unit resistance causes low fuel level readings. Low
resistance causes high fuel level readings. Sending
unit resistance values are shown in a chart in Spec-
ifications.
OIL PRESSURE GAUGE
The oil pressure gauge gives an indication of en-
gine oil pressure. The combination oil pressure send-
ing unit contains a flexible diaphragm. The
diaphragm moves in response to changes in engine
oil pressure. As the diaphragm moves, sending unit
resistance increases or decreases. High resistance on
the gauge side of the sending unit causes high oil
pressure readings. Low resistance causes low oil
pressure readings. Sending unit resistance values are
shown in a chart in Specifications.
SPEEDOMETER/ODOMETER
The speedometer/odometer gives an indication of
vehicle speed and travel distance. The speedometer
receives a vehicle speed pulse signal from the Vehicle
Speed Sensor (VSS). An electronic integrated circuit
contained within the speedometer reads and analyzes
the pulse signal. It then adjusts the ground path re-
sistance of one electromagnet in the gauge to control
needle movement. It also sends signals to an electric
stepper motor to control movement of the odometer
number rolls. Frequency values for the pulse signal
are shown in a chart in Specifications.
The VSS is mounted to an adapter near the trans-
mission (two-wheel drive) or transfer case (four-wheel
drive) output shaft. The sensor is driven through the
adapter by a speedometer pinion gear. The adapter
and pinion vary with transmission, transfer case,
axle ratio and tire size. Refer to Group 21 - Trans-
mission and Transfer Case for more information.
8E - 2 INSTRUMENT PANEL AND GAUGESÐXJJ

TACHOMETER
The tachometer gives an indication of engine speed
in Revolutions-Per-Minute (RPM). With the engine
running, the tachometer receives an engine speed
pulse signal from the Powertrain Control Module
(PCM). An electronic integrated circuit contained
within the tachometer reads and analyzes the pulse
signal. It then adjusts the ground path resistance of
one electromagnet in the gauge to control needle
movement. Frequency values for the pulse signal are
shown in a chart in Specifications.
TRIP ODOMETER
The trip odometer is driven by the same electronic
integrated circuit as the speedometer/odometer. How-
ever, by depressing the trip odometer reset knob on
the face of the speedometer, the trip odometer can be
reset to zero. The trip odometer is serviced only as a
part of the speedometer/odometer gauge assembly.
VOLTMETER
The voltmeter is connected in parallel with the bat-
tery. With the ignition switch ON, the voltmeter in-
dicates battery or generator output voltage,
whichever is greater.
INDICATOR LAMPS
Indicator lamps are located in two areas within the
cluster. Each of these areas is served by a separate
printed circuit and cluster connector. Those lamps in
the gauge area of the cluster share the gauge area
printed circuit and cluster connector A. Those lamps
in the tell-tale area of the cluster use the tell-tale
printed circuit and cluster (tell-tale) connector B.
Up to ten indicator lamps can be found in the tell-
tale area of the cluster. These lamps are arranged in
five stacked rows with two lamps in each row, located
to the driver's side of the main cluster.
ANTI-LOCK BRAKE SYSTEM LAMP
The Anti-Lock Brake System (ABS) lamp is
switched to ground by the ABS module. The module
lights the lamp when the ignition switch is turned to
the START position as a bulb test. The lamp will
stay on for 3 to 5 seconds after vehicle start-up to in-
dicate a system self-test is in process. If the lamp re-
mains on after start-up, or comes on and stays on
while driving, it may indicate that the ABS module
has detected a system malfunction or that the system
has become inoperative. Refer to Group 5 - Brakes
for more information.
BRAKE WARNING LAMP
The brake warning lamp warns the driver that the
parking brake is applied or that the pressures in the
two halves of the split brake hydraulic system are
unequal. With the ignition switch turned ON, batteryvoltage is supplied to one side of the indicator bulb. A
ground path for the bulb is provided by 3 switches.
The bulb will light when:
²the brake warning switch is closed (indicating un-
equal brake system hydraulic pressures possibly due
to brake fluid leakage)
²the ignition switch is in the START position (bulb
test)
²the parking brake switch is closed (parking brake
is applied).
Refer to Group 5 - Brakes for more information.
COOLANT TEMPERATURE WARNING LAMP
The coolant temperature warning lamp lights
whenever engine coolant temperature is too high.
Battery voltage is supplied to one side of the indica-
tor bulb when the ignition switch is turned ON. The
normally open coolant temperature switch is con-
nected to the other side of the bulb. When coolant
temperature is too high, the switch closes. This pro-
vides a ground path for the indicator bulb, which
causes it to light. The lamp is also grounded and
should light with the ignition switch in the START
position as a bulb test.
FOUR-WHEEL DRIVE INDICATOR LAMPS
PART TIME
On vehicles with Command-Trac 4WD, the Part
Time lamp lights when the transfer case is engaged
in the 4H or 4L position. On vehicles with Selec-Trac
4WD, the Part Time lamp lights when the transfer
case is engaged in the4X4PARTTIME or 4 LO po-
sition. Voltage is supplied to one side of the indicator
bulb. A switch in the transfer case is connected to the
other side of the indicator bulb. When the switch is
closed, a path to ground is provided and the indicator
bulb lights.
FULL TIME
The Full Time lamp is only operational on vehicles
equipped with Selec-Trac 4WD. The Full Time lamp
lights when the transfer case is engaged in the4X4
Full Time position. Voltage is supplied to one side of
the indicator bulb. A switch in the transfer case 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.
GENERATOR WARNING LAMP
The generator warning lamp lights with the igni-
tion switch turned to ON, but should go out when-
ever the engine is running. If the lamp comes on and
stays on while the engine is running, it indicates
that a charging system malfunction exists. One side
of the bulb is connected to ignition-switched battery
feed. The other side of the bulb is switched to ground
by the Powertrain Control Module (PCM).
JINSTRUMENT PANEL AND GAUGESÐXJ 8E - 3

INDICATOR LAMPS
If an individual indicator lamp is inoperative, see
the diagnostic procedure under the heading for that
lamp. If more than one indicator lamp or a combina-
tion of lamps and gauges in the gauge area of the in-
strument cluster is inoperative, see Gauges in this
section for diagnosis.
If more than one indicator lamp in the tell-tale
area of the cluster is inoperative, perform the follow-
ing:
(1) Check fuse 17 (fuse 26 - RHD) in the fuseblock
module. If OK, go to next step. If not OK, replace
fuse.
(2) Check for battery voltage at fuse 17 (fuse 26 -
RHD) with ignition switch in ON position. If OK, go
to next step. If not OK, repair circuit to ignition
switch and/or refer to Group 8D - Ignition Systems
for testing of ignition switch.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Unplug cluster (tell-tale) connector
B.
(4) Connect battery negative cable. Turn ignition
switch to ON. Check for battery voltage at cavities 3,
4, and 14 (cavities 3 and 14 - RHD) of cluster connec-
tor B. If OK, go to next step. If not OK, repair open
circuit to fuse 17 (fuse 26 - RHD) as required.
(5) Turn ignition switch to OFF. Disconnect battery
negative cable. Probe cavity 16 (cavity 1 - RHD) of
cluster connector B. Check for continuity to a good
ground. There should be continuity. If OK, replace
cluster tell-tale printed circuit. If not OK, repair open
circuit to ground as required.
ANTI-LOCK BRAKE SYSTEM LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the ABS lamp stays on with the ig-
nition switch in the ON position, or comes on and
stays on while driving, refer to Group 5 - Brakes for
diagnosis. If no ABS problem is found, the following
procedure will help locate a short or open in the ABS
lamp circuit.
(1) Disconnect battery negative cable. Remove in-
strument cluster bezel and cluster assembly. Discon-
nect ABS control module connector.
(2) Install a jumper wire between cavity 6 of clus-
ter (tell-tale) connector B and a good ground. Connect
battery negative cable and turn ignition switch to
ON. Lamp should light. If OK, remove jumper wire
and go to next step. If not OK, replace bulb.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable and unplug cluster connector B. Check
for continuity between cavity 6 of cluster connector B
and a good ground. There should be no continuity. If
OK, go to next step. If not OK, repair short circuit as
required.(4) Check continuity between cavity 6 of cluster
connector B and cavity 52 of ABS control module con-
nector (Fig. 6). There should be continuity. If OK, re-
fer to Group 5 - Brakes for diagnosis of ABS control
module. If not OK, repair open circuit as required.
BRAKE WARNING LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the brake warning lamp stays on
with the ignition switch in the ON position and the
parking brake released, refer to Group 5 - Brakes for
diagnosis. If no service brake or parking brake prob-
lem is found, the following procedure will help locate
a short circuit or faulty switch.
(1) Unplug parking brake switch connector. Turn
ignition switch to START position. Lamp should
light. Release ignition switch to ON position. Lamp
should go OFF. If OK, go to step 10. If not OK, go to
next step.
(2) Unplug brake warning switch connector. Install
a jumper wire between two cavities of connector.
Turn ignition switch to START. Lamp should light.
Remove jumper wire and lamp should go off. If OK,
replace brake warning switch. If not OK, remove
jumper wire and go to next step.
(3) Turn ignition switch to ON position. Install a
jumper wire between cavity B (cavity A - RHD) of
brake warning switch connector and a good ground.
Lamp should light. If OK, go to step 5. If not OK, go
to next step.
(4) Turn ignition switch to OFF. Remove jumper
wire and disconnect battery negative cable. Remove
instrument cluster bezel and cluster assembly. Install
a jumper wire between cavity 8 (cavity 9 - RHD) of
cluster (tell-tale) connector B and a good ground.
Fig. 6 ABS Control Module Connector
8E - 12 INSTRUMENT PANEL AND GAUGESÐXJJ

Connect battery negative cable and turn ignition
switch to ON. Lamp should light. If OK, repair open
circuit to brake warning switch. If not OK, replace
bulb.
(5) Turn ignition switch to OFF and remove
jumper wire. Disconnect battery negative cable.
Check for continuity between cavity A (cavity B -
RHD) of brake warning switch connector and a good
ground with ignition switch in START position.
There should be continuity. If not OK, go to next
step.
(6) Turn ignition switch to OFF and remove
jumper wire. Disconnect battery negative cable. Un-
plug ignition switch connector. Check for continuity
between ignition switch connector cavity 3 and a
good ground. There should be no continuity. If OK, go
to next step. If not OK, repair short circuit between
ignition switch and brake warning switch connectors
as required.
(7) Check for continuity between ignition switch
connector cavity 3 and brake warning switch connec-
tor cavity A (cavity B - RHD). There should be conti-
nuity. If OK, go to next step. If not OK, repair open
circuit as required.
(8) Check for continuity between metal steering
column jacket and a good ground. There should be
continuity. If OK, go to next step. If not OK, refer to
Group 19 - Steering to check steering column ground
clip installation.
(9) Turn ignition switch to START position and
hold there. Check for continuity between terminal 3
of ignition switch and a good ground. There should
be continuity. If not OK, replace ignition switch.
(10) Unplug brake warning switch connector.
Check for continuity between parking brake switch
connector and a good ground. There should be no
continuity. If OK, go to next step. If not OK, repair
short circuit as required.
(11) Check for continuity between parking brake
switch connector and cavity B (cavity A - RHD) of
brake warning switch connector. There should be
continuity. If OK, replace parking brake switch. If
not OK, repair open circuit to brake warning switch
as required.
COOLANT TEMPERATURE WARNING LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the problem being diagnosed is re-
lated to lamp accuracy, be certain to confirm that
problem is with lamp and not with cooling system
performance. Actual engine coolant temperature
should be checked with a test gauge or thermometer
before proceeding with lamp diagnosis. Refer to
Group 7 - Cooling System for more information.
(1) Turn ignition switch to START position. Lamp
should light. If OK, go to next step. If not OK, go to
step 3.(2) Turn ignition switch to ON. Disconnect coolant
temperature switch connector (Fig. 1). Jump switch
connector to ground. Lamp should light. If OK, re-
place switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Unplug coolant temperature switch
connector. Remove instrument cluster bezel and clus-
ter assembly. Disconnect cluster connector A and
probe cavity A1. Check for continuity to a good
ground. There should be no continuity. If OK, go to
next step. If not OK, repair short circuit to coolant
temperature switch or ignition switch as required.
(4) Connect cluster connector A to cluster. Install a
jumper wire from cavity A1 of cluster connector A to
a good ground. Connect battery negative cable and
turn ignition switch to ON. Lamp should light. If OK,
repair open circuit to coolant temperature switch or
ignition switch as required. If not OK, replace bulb.
FOUR-WHEEL DRIVE INDICATOR LAMPS
(1) Apply parking brake, start engine, vehicle in
4WD Lock or 4WD.
(2) Unplug switch and touch harness side of wire
to ground. Lamp should light. If OK, check switch
operation, replace if bad. If bulb is OK, repair open
to indicator.
GENERATOR WARNING LAMP
(1) Disconnect battery negative cable and unplug
PCM connector. Install a jumper wire between cavity
36 of PCM connector (Fig. 5) and a good ground. Con-
nect battery negative cable and turn ignition switch
to ON. Lamp should light. Unplug jumper wire and
lamp should go off. If OK, refer to Powertrain Diag-
nostic Procedures to check PCM. If not OK, go to
next step.
(2) Turn ignition switch to OFF and disconnect
battery negative cable. Remove instrument cluster
bezel and cluster assembly. Install a jumper wire be-
tween cavity B8 of cluster connector A and a good
ground. Connect battery negative cable and turn ig-
nition switch to ON. Lamp should light. If OK, go to
next step. If not OK, replace bulb.
(3) Turn ignition switch to OFF and disconnect
battery negative cable. Unplug cluster connector A.
Probe cavity B8 of cluster connector A and check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(4) Check for continuity between cavity B8 of clus-
ter connector A and cavity 36 of PCM connector.
There should be continuity. If not OK, repair open
circuit as required.
HEADLAMP HIGH BEAM INDICATOR LAMP
(1) Check that headlamp high beams are func-
tional. If OK, go to next step. If not OK, refer to
Group 8L - Lamps for diagnosis of headlamp system.
JINSTRUMENT PANEL AND GAUGESÐXJ 8E - 13

(3) Reach under the instrument panel and depress
the switch shaft release/retainer button (Fig. 14).
Pull the switch control knob and shaft outward.
(4) Remove the headlamp switch retaining nut
from the front of the instrument panel (Fig. 15).(5) Disconnect the wire harness connector from the
switch.
(6) Remove the headlamp switch from the instru-
ment panel.
(7) Reverse removal procedures to install.
INSTRUMENT PANEL REMOVE/INSTALL
(1) Disconnect battery negative cable.
(2) Remove the following (Fig. 16):
²parking brake release handle
²lower heat/AC duct below steering column
²ash receiver
²lower instrument panel
²cluster bezel
²cluster assembly
²radio
²climate control panel
²instrument panel switches
²headlamp switch
²antenna connector
²blower motor resistors
²ground lead
²unplug glove box lamp
²defroster cowl outlet panel
Remove driver's side heat/AC outlet to gain
access to driver's side defroster cowl outlet
panel retaining clip to aid in removal (Fig. 17).
²instrument panel attaching bolts
²steering column attaching bolts
²instrument panel assembly.
The instrument panel wiring harness is at-
tached to the back of the instrument panel as-
sembly and must be installed correctly.
(3) To install instrument panel, position instru-
ment panel assembly on side mounting bolts (Fig.
18).
(4) Route wiring harnesses and secure instrument
panel assembly mounting points.
(5) Connect tube to lap cooler.
(6) Reverse removal procedures to complete instal-
lation.
Fig. 13 Printed Circuit And Cluster Connector
Fig. 14 Headlamp Switch Knob And Shaft Remove/
Install
Fig. 15 Headlamp Switch Remove/Install
8E - 20 INSTRUMENT PANEL AND GAUGESÐXJJ

INSTRUMENT PANEL AND GAUGESÐYJ
CONTENTS
page page
INSTRUMENT PANEL AND GAUGESÐYJ..... 22
DIAGNOSIS............................ 23
GENERAL INFORMATION................. 20SERVICE PROCEDURES.................. 31
SPECIFICATIONS........................ 39
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
and heater components can be accessed without com-
plete instrument panel removal.
Removal of the left instrument cluster bezel allows
access to the main cluster assembly and most
switches. Removal of the center cluster bezel allows
access to the gauge package cluster assembly, the
heater controls, and the radio. Removal of the cluster
assemblies allows access to the individual gauges, il-
lumination and indicator lamp bulbs, printed cir-
cuits, and most wiring.
INSTRUMENT CLUSTERS
The instrument cluster used on YJ (Wrangler) mod-
els consists of two separate assemblies. The main
cluster assembly is located on the left side of the in-
strument panel, centered over the steering column
opening. The gauge package cluster assembly is lo-
cated near the center of the instrument panel. Each
cluster assembly is served by a separate printed cir-
cuit and wiring connector. Some variations of each
cluster exist due to optional equipment and regula-
tory requirements.
The main cluster assembly includes a speedometer/
odometer/trip odometer and a tachometer. It also in-
cludes provisions for the following indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²headlamp high beam indicator lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp²turn signal indicator lamps
²upshift indicator lamp.
The gauge package cluster assembly includes a
four-wheel drive indicator lamp and the following
gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²voltmeter.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the
two cluster printed circuits. With the ignition switch
in the OFF position, voltage is not supplied to the
gauges. A gauge pointer may remain within the
gauge scale after the ignition switch is OFF. How-
ever, the gauges do not accurately indicate any vehi-
cle condition unless the ignition switch is ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
8E - 24 INSTRUMENT PANEL AND GAUGESÐYJJ