1994 JEEP CHEROKEE fuel pressure

DIAGNOSTICS/SERVICE PROCEDURES
INDEX
page page
Automatic Shut Down (ASD) Relay............ 8
Camshaft Position Sensor Test............... 8
Crankshaft Position Sensor Test.............. 9
Distributor Cap........................... 9
Distributor Rotor......................... 10
DRB Scan Tool.......................... 10
Engine Coolant Temperature Sensor Test...... 12
General Information........................ 8
Ignition Coil............................. 11
Ignition Secondary Circuit Diagnosis.......... 12Ignition Timing........................... 14
Intake Manifold Air Temperature Sensor Test . . . 14
Manifold Absolute Pressure (MAP) Sensor Test . 14
On-Board Diagnostics (OBD)................ 19
Oxygen Sensor Tests..................... 19
Powertrain Control Module (PCM)............ 15
Spark Plug Secondary Cables............... 17
Spark Plugs............................ 16
Throttle Position Sensor Test............... 18
GENERAL INFORMATION
This section of the group, Diagnostics/Service Pro-
cedures, will discuss basic ignition system diagnos-
tics and service adjustments.
For system operation and component identification,
refer to the Component Identification/System Opera-
tion section of this group.
For removal or installation of ignition system com-
ponents, refer to the Component Removal/Installa-
tion section of this group.
For other useful information, refer to On-Board Di-
agnostics in the General Diagnosis sections of Group
14, Fuel System in this manual.
For operation of the DRB Scan Tool, refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice manual.
AUTOMATIC SHUT DOWN (ASD) RELAY
Refer to RelaysÐOperation/Testing in the Group
14, Fuel System section of this service manual.
CAMSHAFT POSITION SENSOR TEST
The camshaft position sensor is located in the dis-
tributor on all engines.
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
2.5L OR 4.0L ENGINE
For this test, an analog voltmeter is needed.Do
not remove the distributor connector from the dis-
tributor. Using small paper clips, insert them into
the backside of the distributor wire harness connec-
tor to make contact with the terminals. Be sure that
the connector is not damaged when inserting the pa-
per clips. Attach voltmeter leads to these paper clips.
(1) Connect the positive (+) voltmeter lead into
the sensor output wire. This is at done the distribu-
tor wire harness connector. For wire identification,
refer to Group 8W, Wiring Diagrams.(2) Connect the negative (-) voltmeter lead into the
ground wire. For wire identification, refer to Group
8W, Wiring Diagrams.
(3) Set the voltmeter to the 15 Volt DC scale.
(4) Remove distributor cap. Rotate (crank) engine
with starter until pulse ring (Fig. 1) enters the mag-
netic pickup on camshaft position sensor. Distributor
rotor should be pointed in 9 o'clock position. The
movable pulse ring should now be within the sensor
pickup.
(5) Turn ignition key to ON position. Voltmeter
should read approximately 5.0 volts.
(6) If voltage is not present, check the voltmeter
leads for a good connection.
(7) If voltage is still not present, check for voltage
at the supply wire. For wire identification, refer to
Group 8W, Wiring Diagrams.
Fig. 1 Pulse Ring/Rotor PositionÐTypical
8D - 8 IGNITION SYSTEMSJ

(10) If spark is not produced, replace the ignition
coil.
IGNITION TIMING
Base (initial) ignition timing is NOT adjustable
on any of the 2.5L 4 cylinder or 4.0L 6 cylinder
engines. Do not attempt to adjust ignition timing
by rotating the distributor.
Do not attempt to modify the distributor hous-
ing to get distributor rotation. Distributor posi-
tion will have no effect on ignition timing.
All ignition timing functions are controlled by the
powertrain control module (PCM). Refer to On-Board
Diagnostics in the Multi-Port Fuel InjectionÐGen-
eral Diagnosis section of Group 14, Fuel Systems for
more information. Also refer to the appropriate Pow-
ertrain Diagnostics Procedures service manual for
operation of the DRB Scan Tool.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
(1) Disconnect the wire harness connector from the
sensor (Figs. 18 or 19).
(2) Test the resistance of the sensor with a input
impedance (digital) volt-ohmmeter. Do not remove
the sensor from the engine for testing. For resistance
values, refer to the Sensor Resistance chart. Replace
the sensor if it is not within the range of resistance
specified in the chart.
(3) Test the resistance of the wire harness. This is
done between the Powertrain Control Module (PCM)
wire harness connector terminal-21 and the sensor
connector terminal. Also check continuity between
terminal-4 to the sensor connector terminal. Repair
the wire harness as necessary if the resistance is
greater than 1 ohm.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
The MAP sensor is located on the cowl panel near
the rear of the engine cylinder head (valve) cover
(Fig. 20).
(1) Inspect the sensor vacuum hose connections at
the throttle body and sensor (Fig. 20). Repair as nec-
essary.
CAUTION: When testing the sensor, be sure that
the harness wires are not damaged by the test
meter probes.Fig. 18 Air Temperature SensorÐ2.5L Engine
Fig. 19 Air Temperature SensorÐ4.0L Engine
SENSOR RESISTANCE (OHMS)
8D - 14 IGNITION SYSTEMSJ

INSTRUMENT PANEL AND GAUGES
GROUP INDEX
page page
INSTRUMENT PANEL AND GAUGESÐXJ..... 1INSTRUMENT PANEL AND GAUGESÐYJ.... 14
INSTRUMENT PANEL AND GAUGESÐXJE
CONTENTS
page page
INSTRUMENT CLUSTER DIAGNOSIS........ 3
INSTRUMENT CLUSTER GENERAL INFORMATION.. 1
INSTRUMENT CLUSTER SERVICE PROCEDURES... 5
SPECIFICATIONS....................... 13
INSTRUMENT CLUSTER GENERAL INFORMATION
INDEX
page page
4WD Indicator Lamp........................ 2
Anti-Lock Brake Indicator Lamp............... 2
Brake Indicator Lamp....................... 2
Coolant Temperature Gauge................. 1
Coolant Temperature Indicator Lamp........... 1
Fuel Gauge.............................. 2
Low Fuel Warning Lamp..................... 2Malfunction Indicator Lamp (Check Engine)...... 2
Oil Pressure Gauge....................... 1
Oil Pressure Indicator Lamp.................. 1
Speedometer/Odometer System.............. 2
Tachometer.............................. 2
Upshift Indicator Lamp...................... 2
Voltmeter............................... 1
With the ignition switch in the ON or START posi-
tion, voltage supplied to the instrument cluster is lim-
ited by fuse #17. The voltage is supplied to all the
gauges and indicator lamps through the instrument
cluster printed circuit.
With the ignition switch in the OFF position, volt-
age is not supplied to the instrument cluster and the
gauges do not indicate any vehicle condition.
VOLTMETER
The voltmeter measures battery or generator out-
put voltage, whichever is greater.
OIL PRESSURE GAUGE
The oil pressure 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 position. The oil pressure sender is a variable
resistor that changes electrical resistance with a change
in oil pressure (values shown in Specifications chart).
OIL PRESSURE INDICATOR LAMP
Voltage is supplied to one side of the indicator bulb
and the oil pressure switch is connected to the other
side. When oil pressure is too low the switch closes
providing a path to ground, and the indicator bulb
lights.
COOLANT TEMPERATURE GAUGE
The coolant temperature 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 position. The coolant tem-
perature sensor is a thermistor that changes electri-
cal resistance with a change in coolant temperature
(values shown in Specifications chart).
COOLANT TEMPERATURE INDICATOR LAMP
Voltage is supplied to one side of the indicator bulb
and the coolant temperature switch is connected to the
JINSTRUMENT PANEL AND GAUGES 8E - 1

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 CLUSTER DIAGNOSIS
INDEX
page page
4WD Indicator Inoperative................... 4
Anti-Lock Indicator......................... 4
Brake Indicator Inoperative.................. 4
Coolant Temperature Gauge Inoperative........ 3
Coolant Temperature Indicator Inoperative....... 3
Fuel Gauge Inoperative..................... 3
Gauges and Indicators Inoperative............ 3
Instrument Panel Lamps.................... 4
Low Fuel Warning Inoperative................ 4
Low Washer Indicator Inoperative............. 4Malfunction Indicator Lamp (Check Engine)...... 4
Oil Pressure Gauge Inoperative............... 3
Oil Pressure Indicator Inoperative............. 3
Radio/Clock Illumination.................... 4
Seat Belt Indicator........................ 4
Speedomete/Odometer Inoperative............. 3
Tachometer Inoperative..................... 3
Upshift Indicator Inoperative................. 4
Voltmeter Inoperative....................... 3
SPEEDOMETER/ODOMETER INOPERATIVE
(1) Check for continuity in the wire between the
vehicle speed sensor and cluster connector pin A5.
(2) With the ignition switch in the ON position,
check for battery voltage across pin A8 (B+) and pin
B2 (ground).
(3) Perform vehicle speed sensor test. Refer to the
appropriate vehicle Diagnostic Test Procedures man-
ual.
(4) If all the previous tests prove good, replace
speedometer/odometer.
GAUGES AND INDICATORS INOPERATIVE
(1) Remove and inspect fuse #17. Replace as re-
quired.
(2) Measure resistance at instrument cluster con-
nector terminal A3. Meter should read zero ohms. If
not, repair open to ground.
VOLTMETER INOPERATIVE
(1) Turn ignition switch to ON. Voltmeter should
read battery voltage. If not, go to step 2.
(2) Measure voltage at instrument cluster connec-
tor terminal A8. Meter should read battery voltage.
If OK, replace meter. If not, repair open to fuse #17.
OIL PRESSURE GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect oil pressure sender connector (Fig.
1). Needle goes to H. If not, go to step 3.
(3) Touch oil pressure sender connector to ground.
Needle goes to L. If OK, replace sender. If not, repair
open to gauge (instrument cluster connector terminal
B7).
OIL PRESSURE INDICATOR INOPERATIVE
(1) Turn ignition switch to ON.
(2) Touch oil pressure switch connector to ground.
Lamp should light. If OK, replace switch. If bulb is
OK, repair open to instrument cluster connector ter-
minal B7.
COOLANT TEMPERATURE GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect coolant temperature sender connec-
tor. Needle goes to C. If not, go to step 3.
(3) Touch coolant temperature sender connector to
ground. Needle goes to H. If OK, replace sender. If
not, repair open to gauge (instrument cluster connec-
tor terminal A1).
COOLANT TEMPERATURE INDICATOR
INOPERATIVE
(1) Turn ignition switch to ON.
(2) Touch coolant temperature indicator connector
to ground. Lamp should light. If OK, replace switch.
If bulb is OK, repair open to instrument cluster con-
nector terminal A1.
TACHOMETER INOPERATIVE
Tachometer input is from the Powertrain Control
Module pin 43. Use the DRB scan tool to test.
FUEL GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect fuel gauge sender connector. Needle
should go to E.
Fig. 1 Oil Pressure Sending UnitÐ4.0L
JXJ INSTRUMENT PANEL AND GAUGES 8E - 3

DIAGNOSINGÐALL LAMPS OUT
(1) Inspect fuse #9. Replace as required.
(2) Measure voltage at instrument cluster connec-
tor terminal 20. Meter should read zero ohms. If not,
repair open to ground.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have
an optional upshift indicator lamp. The lamp is con-
trolled by the PCM. The lamp lights to indicate when
the driver should shift to the next highest gear for best
fuel economy. The PCM 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 it is turned off
when the engine is started. The lamp will be lighted
during engine operation according to engine speed
and load.
(1) Turn ignition switch to ON.
(2) Ground pin 2 of cluster connector. Lamp should
light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for conti-
nuity between cluster connector pin 2 and pin 54 of
the PCM. If not, repair open. If OK, refer to DRB
scan tool actuator test of upshift indicator.
BRAKE INDICATOR LAMP
The brake indicator is a dual function lamp. It will in-
dicate an unequal pressure condition in the split brake
hydraulic system and it also will indicate when the park-
ing brake is engaged. Separate switches are used for each
indicator lamp function. A switch mounted on the brake
pedal assembly will close a ground circuit whenever the
parking brakes are applied. A second switch is installed
in the brake hydraulic lines near the master cylinder. If
the switch is balanced by equal pressure on both ends of
the switch valve, the valve remains centered and the
lamp remains off. If the valve is shifted by unequal pres-
sure between the front or rear brake hydraulic systems,
the lamp circuit is connected to ground. To make sure
the brake lamp is functional before the vehicle is driven,
it is illuminated through a ground circuit when the igni-
tion switch is turned to the START position.
(1) Turn ignition switch to ON.
(2) Ground pin 1 of the cluster connector. Lamp
should light. If not, replace bulb. If OK, continue
with step 3.
(3) Turn ignition switch to OFF. Check for continuity to
park brake switch and brake warning switch.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE)
The Malfunction Indicator Lamp (Check Engine) il-
luminates 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 fault is de-
clared the PCM will go into a limp-in mode in an
attempt to keep the system operating. It signals 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 DTC's stored in the PCM memory to be dis-
played in a series of flashes representing digits.
(1) Turn ignition switch to ON.
(2) Ground pin 4 of cluster connector. Lamp should
light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for conti-
nuity between cluster connector pin 4 and PCM cav-
ity 32. If OK, replace PCM. If not, repair open.
SEAT BELT REMINDER LAMP
Apply 12 volts to terminal 16 of cluster connector.
Lamp should light. If not, replace bulb. If OK, check
wiring for an open to buzzer module. Refer to Group
8U - Chime/Buzzer Warning Systems.
INSTRUMENT PANEL ILLUMINATION LAMPS
The instrument panel illumination lamps share
two common connections. There is a splice after fuse
#10 that connects the lamps to battery feed. There is
also a splice that connects all lamps to ground. Be-
cause they share these common connection points in
a parallel circuit, the illumination lamps will all
come on at the same time. It also means one or more
lamps can be out without affecting the operation of
the other lamps.
On the battery side of the circuit, the headlamp
switch illumination rheostat/switch and panel lamps
fuse receive battery feed in series from the park/tail
fuse. In the park lamp position, the headlamp switch
completes the circuit from the park/tail fuse to the il-
lumination rheostat/switch and panel lamps fuse.
The illumination rheostat contains a variable resis-
tor that allows the driver to vary illumination inten-
sity from off to full brightness.
DIAGNOSIS
(1) Turn parking lamps ON.
(2) Check fuse #10. Replace as required.
(3) Measure voltage at battery side of fuse #10
with rheostat turned counterclockwise to clockwise
(LO to HI). Meter should read zero volts to battery
voltage. If not, replace headlamp switch.
(4) Measure resistance at ground side of fuse #10
with parking lamps OFF. Meter should read almost
zero ohms (except bulb filament). If not, repair open
to ground. If zero ohms, 12 volt supply wire from fuse
is shorted to ground, repair short.
8E - 16 YJ INSTRUMENT PANEL AND GAUGESJ

GAUGE PACKAGE GENERAL INFORMATION
The gauge package contains 4 gauges and the 4
wheel drive indicator. The gauges have a common
battery feed from fuse #9 and ignition switch. Al-
though they have separate power sources, the 4
gauges share a common ground connection.
The voltmeter indicates electrical system voltage.
When the engine is not running, the voltage regis-
tered is from the battery. After the engine is started,
charging system voltage is indicated. In the gauge
package, the voltmeter forms a parallel connectionacross the battery feed and ground.
The remaining gauges - oil pressure, fuel and cool-
ant temperature - are connected to individual sender
units. Variable resistors in the senders will change
the amount of current allowed to flow through the
gauge coils. As current flow through the coils varies,
the position of the indicator needle also will vary.
The 4 gauges are connected to battery feed, ground
and the sender units through a printed circuit
mounted on the back of the gauge housing.
GAUGE PACKAGE DIAGNOSIS
ALL GAUGES INOPERATIVE (Fig. 15)
(1) Check the fuse #9. Replace as required.
(2) Turn ignition switch to ON and measure volt-
age at battery side of fuse #9. Meter should read bat-
tery voltage. If not, repair open from ignition switch.
(3) Unplug gauge package connector from gauge
package.
(4) Turn ignition switch to OFF and measure resis-
tance from instrument cluster connector terminals 1
and 13 to a clean chassis ground. Meter should read
zero ohms. If not, repair open to ground.
(5) Turn ignition switch to ON and measure volt-
age at instrument cluster connector terminals 2 and
12. Meter should read battery voltage. If not, repair
open from fuse panel.
ONE GAUGE INOPERATIVE
Does not apply to voltmeter.
OIL PRESSURE SENDER
(1) Turn ignition switch to ON.
(2) Unplug oil pressure sender connector from oil
pressure sender.
(3) Touch connector to engine block (ground).
Gauge should read at low end of scale.
(4) When connector is NOT touching ground (open
circuit) gauge should read at high end of scale. If OK
replace sender. If not, proceed with step 5.
(5) Check circuit between sender and gauge for an
open. Repair as required. If wiring is OK, replace
gauge.
COOLANT TEMPERATURE SENDER
(1) Turn ignition switch to ON.
(2) Unplug coolant temperature sender connector
from coolant temperature sender.
(3) Touch connector to engine block (ground).
Gauge should read at high end of scale.
(4) When connector is NOT touching ground (open
circuit) gauge should read at low end of scale. If OK
replace sender. If not, proceed with step 5.
(5) Check circuit between sender and gauge for an
open. Repair as required. If wiring is OK, replace
gauge.
FUEL GAUGE SENDER
(1) Turn ignition switch to ON.
(2) Separate fuel gauge sender connector from fuel
gauge sender near tank.
(3) Ground the center wire of the body harness
side of the connector. The gauge should read at low
end of scale. If OK, check sending unit (step 4). If
not, check circuit between connector and gauge. Re-
pair as required. If circuit is OK, replace gauge.
(4) Turn ignition switch to OFF.
(5) Measure resistance from fuel gauge sender con-
nector center terminal to a clean chassis ground.
Meter readings should correspond to those shown in
Specifications. If not OK, replace sender. If OK, re-
pair open from fuel gauge sender connector to
ground.
PRINTED CIRCUIT
(1) Turn ignition switch to ON.
(2) Unplug gauge package connector from gauge
package.
(3) Measure resistance from gauge package termi-
nal 12 (fuel and coolant temperature gauge) or from
terminal 2 (voltmeter and oil pressure gauge) to
gauge battery terminal. Meter should read zero
ohms. If not, replace/repair printed circuit.
(4) Measure resistance from gauge package termi-
nal 13 (fuel and coolant temperature gauge) or from
terminal 1 (voltmeter and oil pressure gauge) to
gauge ground terminal. Meter should read zero
ohms. If not, replace/repair printed circuit. If zero
ohms, replace gauge.
GAUGE CALIBRATION VALUES
Use the charts in Specifications. The calibration of
the gauge can be checked. If the indicator needle is
not in the correct position, replace the gauge.
4WD INDICATOR
The four-wheel drive indicator lamp circuit is com-
pleted by the Command-Trac switch located below
the battery.
8E - 22 YJ INSTRUMENT PANEL AND GAUGESJ

Wiring Diagram Name Sheet Number
Left Fog Lamp.............................27
Left Headlamp.............................27
Left Park and Turn Signal Lamp.................27
Left Side Marker Lamp.......................27
Right Fog Lamp............................28
Right Headlamp............................28
Right Park and Turn Signal Lamp................28
Right Side Marker Lamp......................28
Fuel Gauge................................44
Fuel Injection Ignition System
2.5L Engine.................11, 12, 13, 14, 15, 16
Automatic Shut Down Relay....................11
Camshaft Position Sensor.....................12
Crankshaft Position Sensor.....................12
Data Link Connector.........................13
Engine Coolant Temperature Sensor...............15
Fuel Injectors.............................14
Fuel Pump Relay...........................11
Heated Oxygen Sensor.......................11
Idle Air Control Motor........................14
Ignition Coil..............................13
Intake Air Temperature Sensor..................15
MAP Sensor..............................15
Power Steering Switch.......................14
Powertrain Control Module (PCM) . . .11, 12, 13, 14, 15, 16
Throttle Position (Sensor).....................15
Vehicle Speed Sensor........................12
Fuel Injection Ignition System
4.0L Engine.................17, 18, 19, 20, 21, 22
Automatic Shut Down Relay....................17
Camshaft Position Sensor.....................18
Crankshaft Position Sensor.....................18
Data Link Connector.........................19
Engine Coolant Temperature Sensor...............21
Fuel Injectors.............................20
Fuel Pump Relay...........................17
Heated Oxygen Sensor.......................17
Idle Air Control Motor........................20
Ignition Coil..............................19
Intake Air Temperature Sensor..................21
MAP Sensor..............................21
Powertrain Control Module (PCM) . . .17, 18, 19, 20, 21, 22
Throttle Position (Sensor).....................21
Vehicle Speed Sensor........................18
Fuel Injectors............................14, 20
Fuel Pump Relay..........................11, 17
Fuel Tank System............................55
Fuel Tank Sending Unit.........................55
Fuse Application Chart........................1,2
Fuses
1 .................................2,10,37
3 ..............................1,30,34,36
4 .................................2,10,34
5 ..............................2,10,13,19
6 .................................1,30,53
7 ..............................2,10,24,46
8 ...................................1,29
9 .................................2,10,36Wiring Diagram Name Sheet Number
10 ...................................1,31
11 .............................2,10,38,39
12 ...........................2,10,47,48,50
F13 ..................................2,58
F15 ..............................2,4,6,33
F16 ............................2,4,6,8,35
Fuse Panel..............................61, 62
Gauge Package Connector.......................43
Gauges
Electronic Speedometer.......................42
Electronic Tachometer........................42
Engine Coolant Temperature Gauge...............44
Engine Oil Pressure Gauge.....................44
Fuel Gauge...............................44
Voltmeter................................44
Generator................................3,5
Hazard Signal Flasher..........................34
Headlamps.........................25, 26, 27, 28
Headlamp Switch........................1,29,30
Dimmer Switch............................29
Headlamp Switch...........................29
Heated Oxygen Sensor......................11, 17
Heated Rear Window Relay......................54
Heated Rear Window Switch.....................53
Heated Rear Window System..................53, 54
Heated Rear Window Grid.....................53
Heated Rear Window Relay....................54
Heated Rear Window Switch....................53
Timer..................................54
Heater Control Panel Illumination..................32
Heater System..............................47
Blower Motor.............................47
Blower Resistor............................47
Blower Switch.............................47
Heater/Off Switch...........................47
Horn.....................................33
Horn Brush/Slip Ring........................33
Horn Relay...............................33
Horn Switch..............................33
Hydraulic Actuation Unit........................58
Idle Air Control Motor.......................14, 20
Ignition Coil.............................13, 19
Ignition Key Warning Switch.....................36
Ignition Switch..........................2,9,10
Instrument Panel Illumination Lamps................32
Intake Air Temperature Sensor.................15, 21
Intermittent Wiper Module.......................40
Intermittent Wiper System....................39, 40
Intermittent Wiper Module.....................40
Park Switch..............................39
Washer Pump.............................39
Wiper Motor..............................39
Wiper/Washer Switch........................40
W/Wiper Circuit Breaker (5.3 Amp)...............39
Lamps
Center High Mounted Stop Lamps................52
Dome Lamp..............................35
Instrument Panel Illumination Lamp...............32
8W - 74 WIRING DIAGRAMSJ