1995 JEEP CHEROKEE Service Repair Manual

manual radio set spare wheel load capacity child seat handbrake coolant

Page 305 of 2198

JEEP CHEROKEE 1995 Service Repair Manual DIAGNOSIS
COMPASS/DISPLAY SELF-DIAGNOSTIC TEST
This self-diagnostic test is used to determine that
the compass and all of its display segments are oper-
ating properly electrically. Initiate the self-

DIAGNOSIS
COMPASS/DISPLAY SELF-DIAGNOSTIC TEST
This self-diagnostic test is used to determine that
the compass and all of its display segments are oper-
ating properly electrically. Initiate the self-diagnostic
test as follows:
(1) With the ignition switch in the OFF position,
simultaneously press and hold the COMP/TEMP but-
ton and the US/METRIC button.
(2) Turn ignition switch to the ON position.
(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 display segments are functional. If any segment
should fail to light during the test, the unit is faulty
and requires replacement. To repeat the test, momen-
tarily depress and release the COMP/TEMP button
one time.
(4) Momentarily depress and release the US/MET-
RIC button one time and all segments will light si-
multaneously for about 2 seconds. If any segment
should fail to light during the test, the unit is faulty
and requires replacement. To repeat the test, momen-
tarily depress and release the COMP/TEMP button
one time.
(5) Momentarily depress and release the US/MET-
RIC button one time or turn the ignition switch to
OFF to exit the self-diagnostic mode and return to
normal operation.
If the compass functions, but accuracy is sus-
pect, it may be necessary to perform a variation
adjustment. This procedure allows the unit to
accommodate variations in the earth's mag-
netic field strength based on geographic loca-
tion. See Compass Variation Adjustment, in this
group.
If the compass display has blanked out and
only CAL appears, demagnetizing may be nec-
essary to remove excessive residual magnetic
fields from the vehicle. See Compass Demagne-
tizing, in this group.
THERMOMETER DIAGNOSIS
The thermometer function is supported by a tem-
perature sensor, a wiring circuit and a portion of the
overhead console display. The sensor is mounted at
the center of the vehicle below the grille, behind the
front bumper (Fig. 1).
If any portion of the circuit fails, it will self-diag-
nose as an open or short circuit. The system will dis-
play SC (short circuit) when the sensor is exposed to
temperatures in excess of 55ÉC (131ÉF) or if the cir-
cuit is shorted. If the temperature is below -40ÉC
(-40ÉF) or an open circuit exists, the system will dis-
play OC (open circuit).To diagnose the temperature sensor, perform the
following procedures. If the sensor and circuit are
OK, then the electronic module is faulty and should
be replaced.
SENSOR TEST
(1) Turn the ignition switch to OFF. Unplug sensor
connector.
(2) Measure resistance of sensor. At -40ÉF the re-
sistance is 336K ohms. At 140ÉF the resistance is
2.488K ohms. Sensor resistance should read between
these two values. If OK, go to Sensor Circuit Test. If
not OK, replace the sensor.
SENSOR CIRCUIT TEST
(1) Turn ignition switch to OFF. Unplug sensor
connector.
(2) Short the pins on the body half of connector us-
ing a jumper wire.
(3) Remove the overhead console as described in
Service Procedures.
(4) Check continuity between cavities 10 and 11 of
overhead console harness connector (Fig. 2). There
should be continuity. If OK, go to next step. If not
OK, repair open circuit as required.
Fig. 1 Temperature Sensor
8C - 2 OVERHEAD CONSOLEJ

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JEEP CHEROKEE 1995 Service Repair Manual (5) Remove jumper wire from temperature sensor
harness connector. Check continuity between cavities
10 and 11 of overhead console harness connector and
a good ground (Fig. 2). There should be no conti

Page 307 of 2198

JEEP CHEROKEE 1995 Service Repair Manual COMPASS/THERMOMETER DIAGNOSIS
8C - 4 OVERHEAD CONSOLEJ

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JEEP CHEROKEE 1995 Service Repair Manual SERVICE PROCEDURES
COMPASS VARIATION ADJUSTMENT
Variance is the difference between magnetic north
and geographic north. In some areas, the difference
between magnetic and geographic north is great
eno

SERVICE PROCEDURES
COMPASS VARIATION ADJUSTMENT
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) Using the map in Fig. 3, find your geographic
location and note the zone number.
(2) Turn ignition switch to the ON position.
(3) Depress both the US/METRIC and COMP/
TEMP buttons. Hold down until VAR is displayed.
This takes about 5 seconds.
(4) Release both buttons.
(5) Press the US/METRIC button to step through
the numbers until the zone number for your area ap-
pears in the display.
(6) Press the COMP/TEMP button to enter this
zone number into compass unit memory.
(7) Confirm correct directions are indicated.
COMPASS CALIBRATION
CAUTION: DO NOT place any external magnets
such as magnetic roof mount antennas, in the vicin-ity of the compass. DO NOT use magnetic tools
when servicing the overhead console.
The compass features a self-calibrating design,
which simplifies the calibration procedure. This fea-
ture automatically updates the compass calibration
while the vehicle is being driven. This takes into ac-
count small changes in residual magnetism the vehi-
cle may acquire during normal use. Do not attempt
to calibrate the compass near large metal objects
such as other vehicles, large buildings or bridges.
Whenever the compass is calibrated manually,
the variation number must also be reset. See
Variation Adjustment Procedure, in this group.
Calibrate the compass manually as follows:
(1) Start the engine.
(2) Depress both the US/METRIC and COMP/
TEMP buttons. Hold down until CAL is displayed.
This takes about 10 seconds and appears about 5 sec-
onds after VAR is displayed.
(3) Release both buttons.
(4) Drive vehicle on a level surface that is away
from large metal objects through 3 or more complete
circles in not less than 48 seconds. The CAL message
will disappear to indicate that the compass is now
calibrated.
If CAL message remains in display, either
there is excessive magnetism near the compass
or the unit is faulty. Repeat the demagnetizing
and calibration procedures at least one more
time.
If the wrong direction is still indicated, the
area selected may be too close to a strong mag-
netic field. Repeat the calibration procedure in
another location.
COMPASS DEMAGNETIZING
The tool used to degauss or demagnetize the for-
ward console attaching screw and roof panel is the
Miller Tool 6029. Equivalent units must be rated as
continuous duty for 110/115 volts and 60Hz. They
must also have a field strength of over 350 gauss at
1/4-inch beyond the tip of the probe.
The degaussing tool is used to demagnetize both
the roof panel and the console forward mounting
screw, as follows:
(1) Be sure the ignition switch is in the OFF posi-
tion before you begin the demagnetizing procedure.
(2) Plug in the degaussing tool, while keeping the
tool at least 2 feet away from the compass unit.
(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 2 seconds.Fig. 3 Variance Settings
JOVERHEAD CONSOLE 8C - 5

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JEEP CHEROKEE 1995 Service Repair Manual (4) With the degaussing tool still energized, slowly
back it away from the screw until the tool is at least
2 feet from the screw head, then unplug the tool.
(5) Place an 8-1/2 X 11 inch piece of pape

(4) With the degaussing tool still energized, slowly
back it away from the screw until the tool is at least
2 feet from the screw head, then unplug the tool.
(5) Place an 8-1/2 X 11 inch piece of paper, oriented
lengthwise from front to rear, on the center line of
the roof at the windshield header (Fig. 4). The pur-
pose of the paper is to protect the roof panel from
scratches and define the area to be demagnetized.
(6) Plug in the degaussing tool, while keeping the
tool at least 2 feet away from the compass unit.
(7) Slowly approach the center line of the roof
panel at the windshield header 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 a slow, back and forth sweeping
motion and allowing 1/2-inch between passes (Fig. 4),
move the tool at least 4 inches either side of the roof
center line and 11 inches back from the windshield
header.
(9) With the degaussing tool still energized, slowly
back it away from the roof panel until the tip is at
least 2 feet from the roof. Then unplug the tool.
(10) Calibrate the compass and adjust variance as
described in this group.OVERHEAD CONSOLE REMOVE/INSTALL
(1) Remove screw forward of the compass unit (Fig.
5).
(2) Flex housing outward while pressing upward to
disengage the housing from the rear bracket (Arrow
1 in Fig. 5).
(3) Slide console rearward until the console de-
taches from the front mounting bracket (Arrow 2 in
Fig. 5).
(4) While pressing up on rear of console (Arrow 1
in Fig. 5), slide console forward, holding front away
from headliner (Arrow 2 in Fig. 5). Move console for-
ward until the rear detaches from headliner and be-
comes free (Fig. 6).
(5) Disconnect wire harnesses from keyless entry
and compass/thermometer modules (Figs. 7 and 8).
(6) Reverse removal procedures to install. Be sure
to flex housing outward near the keyless entry re-
ceiver until the console snaps onto the rear mounting
bracket.
Fig. 4 Roof Demagnetizing Pattern
Fig. 5 Remove/Install Overhead Console
Fig. 6 Remove/Install Overhead Console
8C - 6 OVERHEAD CONSOLEJ

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JEEP CHEROKEE 1995 Service Repair Manual SUNGLASSES STORAGE BIN REMOVE/INSTALL
(1) Open sunglasses storage bin door.
(2) Remove cover plate (Fig. 9).(3) Unhook torque spring from wall and put in
down position as shown by arrow in Fig. 10.
(4

Page 311 of 2198

JEEP CHEROKEE 1995 Service Repair Manual (8) Snap cover plate back in position as shown in
Fig. 9. Some pressure from the inside of the bin may
be required to engage all 6 snaps.
READING/COURTESY LAMP BULB REMOVE/
INSTALL
(1) Make a hook in

Page 312 of 2198

JEEP CHEROKEE 1995 Service Repair Manual IGNITION SYSTEMS
CONTENTS
page page
COMPONENT IDENTIFICATION/SYSTEM
OPERATION........................... 1
COMPONENT REMOVAL/INSTALLATION...... 17
DIAGNOSTICS/SERVICE PROCEDURES....... 6IGNITION SWITC

IGNITION SYSTEMS
CONTENTS
page page
COMPONENT IDENTIFICATION/SYSTEM
OPERATION........................... 1
COMPONENT REMOVAL/INSTALLATION...... 17
DIAGNOSTICS/SERVICE PROCEDURES....... 6IGNITION SWITCHÐXJ MODELS........... 26
IGNITION SWITCHÐYJ MODELS........... 29
SPECIFICATIONS........................ 32
COMPONENT IDENTIFICATION/SYSTEM OPERATION
INDEX
page page
Automatic Shutdown (ASD) Relay.............. 1
Camshaft Position Sensor.................... 2
Crankshaft Position Sensor................... 3
Distributors............................... 4
Engine Coolant Temperature Sensor............ 5
General Information........................ 1Ignition Coil.............................. 4
Intake Manifold Air Temperature Sensor.......... 5
Manifold Absolute Pressure (MAP) Sensor........ 5
Oxygen (O2S) Sensor....................... 5
Powertrain Control Module (PCM).............. 5
Throttle Position Sensor..................... 5
GENERAL INFORMATION
Throughout this group, references are made to par-
ticular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A
chart showing a breakdown of alphabetical designa-
tions is included in the Introduction group at the be-
ginning of this manual.
This section of the group, Component Identifica-
tion/System Operation, will discuss ignition system
operation and will identify ignition system compo-
nents.
For diagnostic procedures and adjustments, refer to
the Diagnostics/Service Procedures section of this
group.
For removal and installation of ignition system
components, refer to the Component Removal/Instal-
lation 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.
An Ignition specifications section is included at the
end of this group. A general Maintenance Schedule
(mileage intervals) for ignition related items can be
found in Group 0, Lubrication and Maintenance. This
schedule can also be found in the Owners Manual.
IGNITION SYSTEMS
A multi-port, fuel injected engine is used on all
models. The ignition system is controlled by the pow-
ertrain control module (PCM) on all engines. The
PCM was formerly referred to as the SBEC or engine
controller.
The ignition system consists of:
²Spark plugs
²Ignition coil
²Secondary ignition cables
²Distributor (contains rotor and camshaft position
sensor)
²Powertrain control module (PCM)
²Crankshaft position sensor
AUTOMATIC SHUTDOWN (ASD) RELAY
The automatic shutdown (ASD) relay is located in
the power distribution center (PDC) near the battery
(Fig. 1 or 2). As one of its functions, it will supply
battery voltage to the ignition coil.
The ground circuit for the ASD relay is controlled
by the powertrain control module (PCM). This is
done through pin/cavity number 51 of the PCM 60-
way connector. The PCM then regulates ASD relay
operation by switching this ground circuit on-and-off.
Also refer to Ignition Coil for additional informa-
tion.
JIGNITION SYSTEMS 8D - 1

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