1995 JEEP CHEROKEE service indicator

SERVICE PROCEDURES
INDEX
page page
Back-Up/Rear Turn Signal/Tail Lamp Bulb
ReplacementÐYJ....................... 28
Center High Mounted Stop Lamp (CHMSL)ÐYJ . . 28
Daytime Running Lights (Canada Only)ÐYJ..... 30
Drl Module ReplacementÐYJ................ 30
Fog Lamp ReplacementÐYJ................. 25
Fog Lamp Switch ReplacementÐYJ........... 26
Fog LampsÐYJ.......................... 23
Front Park/Turn Signal Lamp Bulb ReplacementÐ
YJ ................................... 25
Headlamp Alignment PreparationÐYJ.......... 22Headlamp AlignmentÐYJ................... 22
Headlamp Bulb ReplacementÐYJ............. 23
Headlamp Dimmer Switch ReplacementÐYJ..... 26
Headlamp SwitchÐYJ...................... 26
Headlamp/Fog Lamp Adjustment Using Alignment
ScreenÐYJ............................ 23
Side Marker Lamp Bulb ReplacementÐYJ....... 25
Underhood Lamp Bulb ReplacementÐYJ....... 29
Underhood Lamp ReplacementÐYJ........... 29
Underhood Lamp Service InformationÐYJ....... 28
HEADLAMP ALIGNMENTÐYJ
Headlamps can be aligned using the screen method
provided in this section. Alignment Tool C4466-A or
equivalent can also be used. Refer to instructions
provided with the tool for proper procedures.The
preferred headlamp alignment setting is 0 for
the left/right adjustment and 1(down for the
up/down adjustment.
HEADLAMP ALIGNMENT PREPARATIONÐYJ
(1) Verify headlamp dimmer switch and high beam
indicator operation.
(2) Correct defective components that could hinder
proper headlamp alignment.
(3) Verify proper tire inflation.
(4) Clean headlamp lenses.
(5) Verify that luggage area is not heavily loaded.
(6) Fuel tank should be FULL. Add 2.94 kg (6.5
lbs.) of weight over the fuel tank for each estimated
gallon of missing fuel.
Fig. 1 Headlamp Alignment ScreenÐTypical
8L - 22 LAMPSÐYJ VEHICLESJ

BULB APPLICATIONÐYJ VEHICLES
GENERAL INFORMATION
The following Bulb Application Table lists the lamp
title on the left side of the column and trade number
or part number on the right.
CAUTION: Do not use bulbs that have a higher can-
dle power than the bulb listed in the Bulb Applica-
tion Table. Damage to lamp can result.
Do not touch halogen bulbs with fingers or other
oily surfaces. Bulb life will be reduced.
EXTERIOR LAMPSÐYJ
Back-up .................................................................1156
Center High Mounted Stoplamp ..........................912
Fog ............................................................................H3
Front Side Marker .................................................194
Headlamp/Sealed Beam....................................H6054
Park/Turn Signal..................................................3157
Tail/Stop ................................................................1157
INTERIOR LAMPSÐYJ
Service procedures for most of the lamps in the in-
strument panel, Instrument cluster and switches are
located in Group 8E, Instrument Panel and Gauges.
Some components have lamps that can only be ser-
viced by an Authorized Service Center (ASC) after
the component is removed from the vehicle. Contact
local dealer for location of nearest ASC.Dome/Cargo .........................................................212-2
Glove Compartment ...............................................194
Under Hood ............................................................105
Underpanel Courtesy...............................................89
INDICATOR LAMPS
Service procedures for most of the lamps in the in-
strument panel, instrument cluster and switches are
located in Group 8E, Instrument Panel and Gauges.
A/C Control ...............................................................74
Anti-lock Brake ........................................................74
Ash Receiver .........................................................1891
Brake Warning .........................................................74
Cigar Lighter ............................................................53
Fasten Seat Belts ....................................................74
Four Wheel Drive ....................................................74
Generator ................................................................194
Hazard.......................................................................74
Heater Control .......................................................194
High Beam..............................................................194
Illumination ............................................................194
Low Coolant..............................................................74
Radio ......................................................................ASC
Rocker Switch...........................................................74
Seat Belt ...................................................................74
Shift ...........................................................................74
Turn Signal.............................................................194
8L - 32 LAMPSÐYJ VEHICLESJ

REAR WINDOW DEFOGGER
CONTENTS
page page
DIAGNOSIS............................. 1
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 3
GENERAL INFORMATION
The electrically-heated rear window defogger is an
available option on XJ (Cherokee), and YJ (Wrangler)
models equipped with the hardtop roof option. Fol-
lowing are general descriptions of the major compo-
nents in the rear window defogger system. Refer to
Group 8W - Wiring Diagrams for complete circuit de-
scriptions and diagrams.
REAR WINDOW GLASS GRID
The heated rear window glass has two electrically-
conductive vertical bus bars and a series of horizon-
tal grid lines made of a silver-ceramic material,
which is baked on and bonded to the inside surface of
the glass. The grid lines and bus bars comprise a
parallel electrical circuit.
When the rear window defogger switch is placed in
the ON position, current is directed to the rear win-
dow grid lines through the bus bars. The grid lines
heat the rear window to clear the surface of fog or
snow. Circuit protection for the heated grid circuit is
provided by fuse 18 (XJ) or fuse 6 (YJ) in the fuse-
block module.
The grid lines and bus bars are highly resistant to
abrasion. However, it is possible for an open to occur
in an individual grid line resulting in no current flow
through the line. The grid lines can be damaged or
scraped off with sharp instruments. Care should be
taken in cleaning the glass or removing foreign ma-
terials, decals or stickers. Normal glass cleaning sol-
vents or hot water used with rags or toweling is
recommended.A repair kit is available to repair the grid lines and
bus bars, or to reinstall the heated glass pigtail
wires.
DEFOGGER SWITCH
The rear window defogger switch is mounted in the
instrument panel left of the steering column for XJ,
or right of the steering column for YJ. The switch cir-
cuit is protected by fuse 8 (XJ) or fuse 9 (YJ) in the
fuseblock module. Actuating the switch energizes the
relay and electronic timer. A light-emitting diode
(LED) in the switch (XJ), or a indicator lamp in the
switch (YJ), illuminates to indicate when the system
is turned on. The defogger switch can not be re-
paired. If faulty, the switch must be replaced.
DEFOGGER RELAY/TIMER
The defogger relay/timer is located in the relay cen-
ter on XJ models, or taped to the instrument panel
wiring harness behind the parking brake pedal in the
left cowl side area on YJ models. When the rear de-
fogger switch is actuated, the rear defogger relay is
energized. This causes current to flow through the
grid circuit for approximately 10 minutes, or until
the rear window defogger switch or ignition switch
are turned off.
DIAGNOSIS
SYSTEM TESTS
Electrically-heated rear window defogger operation
can be confirmed in the following manner:
(1) Turn the ignition switch to the ON position.
(2) Turn rear window defogger control switch ON.
(3) Monitor vehicle voltmeter. With the control
switch ON, a distinct needle deflection should be
noted.(4) The rear window defogger operation can be
checked by feeling the glass. A distinct difference in
temperature between the grid lines and adjacent
clear glass can be detected within 3 to 4 minutes of
operation.
(5) Using a DC voltmeter, contact terminal A (Fig.
1) (passenger side) with the negative lead, and termi-
JREAR WINDOW DEFOGGER 8N - 1

minutes). The use of a locating dowel is recom-
mended during assembly to prevent smearing the
material off location.
Mopar Gasket Maker should be applied sparingly
to one gasket surface. The sealant diameter should
be 1.00 mm (0.04 inch) or less. Be certain the mate-
rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo-
cating dowel is recommended during assembly to pre-
vent smearing the material off location.
ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label found
on the engine compartment hood.
(1) Test battery specific gravity. Add water, if nec-
essary. Clean and tighten battery connections.
(2) Test cranking amperage draw (refer to Group
8B, Battery/Starter Service for the proper proce-
dures).
(3) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications).
(4) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces-
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature.
(c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times.
The higher engine speed may help clean out valve
seat deposits which can prevent accurate compres-
sion readings.
CAUTION: DO NOT overspeed the engine.
(d) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for ab-
normal firing indicatorsÐfouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start-
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check.
(g) Insert compression gage adaptor into the
No.1 spark plug hole. Crank engine until maximum
pressure is reached on gauge. Record this pressure
as No.1 cylinder pressure.
(h) Repeat Step 4g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.(j) If cylinder(s) have abnormally low compres-
sion pressures, repeat steps 4a through 4h.
(k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should NOT be disassem-
bled to determine the cause of low compression
unless some malfunction is present.
(5) Clean or replace spark plugs as necessary. Ad-
just gap (refer to Group 8D, Ignition System for gap
adjustment and torque).
(6) Test resistance of spark plug cables (refer to
Group 8D, Ignition System).
(7) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(8) Perform a combustion analysis.
(9) Test fuel pump for pressure (refer to Group 14,
Fuel System for the proper specifications).
(10) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce-
dure).
(11) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(12) For emission controls refer to Group 25, Emis-
sion Controls System for service procedures.
(13) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust-
ments).
(14) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels un-
der the bores and over the crankshaft to keep abra-
sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de-
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from ma-
jor oil distributors.
9 - 2 ENGINESJ

at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.4 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
VIBRATION DAMPER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt and fan
shroud.
(3) Remove the vibration damper retaining bolt
and washer.
(4) Use Vibration Damper Removal Tool 7697 to re-
move the damper from the crankshaft (Fig. 1).
INSTALLATION
(1) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key in position, align the keyway on the vi-
bration damper hub with the crankshaft key and tap
the damper onto the crankshaft.
(2) Install the vibration damper retaining bolt and
washer.
(3) Tighten the damper retaining bolt to 108 Nzm
(80 ft. lbs.) torque.
(4) Install the serpentine drive belt and tighten to
the specified tension (refer to Group 7, Cooling Sys-
tems for the proper specifications and procedures).(5) Connect negative cable to battery.
TIMING CASE COVER OIL SEAL REPLACEMENT
This procedure is done with the timing case cover
installed.
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt.
(3) Remove the vibration damper.
(4) Remove the radiator shroud.
(5) Carefully remove the oil seal. Make sure seal
bore is clean.
(6) Position the replacement oil seal on Timing
Case Cover Alignment and Seal Installation Tool
6139 with seal open end facing inward. Apply a light
film of Perfect Seal, or equivalent, on the outside di-
ameter of the seal. Lightly coat the crankshaft with
engine oil.
(7) Position the tool and seal over the end of the
crankshaft and insert a draw screw tool into Seal In-
stallation Tool 6139 (Fig. 3). Tighten the nut against
the tool until it contacts the cover.
(8) Remove the tools. Apply a light film of engine
Fig. 1 Vibration Damper Removal Tool 7697
Fig. 3 Timing Case Cover Oil Seal Installation
9 - 30 2.5L ENGINEJ

ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
inch). If the measurement differs from specification
by more than 0.076 mm (0.003 inch), ream the guide
bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD:
(1) Use a dial indicator to measure the lateral
movement of the valve stem (stem-to-guide clear-
ance). This must be done with the valve installed in
its guide and just off the valve seat (Fig. 11).
(2) Correct clearance is 0.025-0.0762 mm (0.001-
0.003 inch). If indicated movement exceeds the spec-
ification ream the valve guide to accommodate an
oversize valve stem.
Valve seats must be ground after reaming the
valve guides to ensure that the valve seat is
concentric to the valve guide.
VALVE SPRING TENSION TEST
Use a universal Valve Spring Tester and a torque
wrench to test each valve spring for the specified ten-
sion value (Fig. 12).
Replace valve springs that are not within specifica-
tions.
INSTALLATION
(1) Thoroughly clean the valve stems and the valve
guide bores.
(2) Lightly lubricate the stem.
(3) Install the valve in the original valve guide
bore.
(4) Install the replacement valve stem oil seals on
the valve stems. If the 0.381 mm (0.015 inch) over-
size valve stems are used, oversize oil seals are re-
quired.(5) Position the valve spring and retainer on the
engine cylinder head and compress the valve spring
with Valve Spring Compressor Tool MD-998772A.
(6) Install the valve locks and release the tool.
(7) Tap the valve spring from side to side with a
hammer to ensure that the spring is properly seated
at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.6 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
Fig. 11 Measurement of Lateral Movement of Valve
Stem
Fig. 12 Valve Spring Tester
J4.0L ENGINE 9 - 71

The throttle body has an air control passage that
provides air for the engine at idle (the throttle plate
is closed). The IAC motor pintle protrudes into the
air control passage and regulates air flow through it.
Based on various sensor inputs, the powertrain con-
trol module (PCM) adjusts engine idle speed by mov-
ing the IAC motor pintle in and out of the air control
passage. The IAC motor is positioned when the igni-
tion key is turned to the On position.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
IGNITION COILÐPCM OUTPUT
System voltage is supplied to the ignition coil pos-
itive terminal. The powertrain control module (PCM)
operates the ignition coil.Base (initial) ignition
timing is not adjustable.The PCM adjusts ignition
timing to meet changing engine operating conditions.
The ignition coil is located near the distributor
(Fig. 22).
Refer to Group 8D, Ignition System for additional
information.
MALFUNCTION INDICATOR LAMPÐPCM OUTPUT
The malfunction indicator lamp illuminates each
time the ignition key is turned on. It will stay on for
approximately three seconds as a bulb test. The lamp
is displayed on the instrument panel as the CHECK
ENGINE lamp (Figs. 23 or 24).
If the powertrain control module (PCM) receives an
incorrect signal, or no signal from certain sensors or
emission related systems, the lamp is turned on. This
is a warning that the PCM has recorded a system or
sensor malfunction. In some cases, when a problem is
declared, the PCM will go into a limp-in mode. This
is an attempt to keep the system operating. It signals
an immediate need for service.The lamp can also be used to display a Diagnostic
Trouble Code (DTC). Cycle the ignition switch On-
Off-On-Off-On within three seconds and any codes
stored in the PCM memory will be displayed. This is
done in a series of flashes representing digits. Refer
to On-Board Diagnostics in the General Diagnosis
section of this group for more information.
RADIATOR FAN RELAYÐPCM OUTPUT
XJ MODELS ONLY
The electric radiator cooling fan used in XJ models
(equipped with 4.0L engine, heavy duty cooling
and/or air conditioning) is controlled by the power-
train control module (PCM) through radiator fan re-
lay. The relay is energized when coolant temperature
is above 103ÉC (217ÉF). It will then de-energize when
Fig. 22 Ignition CoilÐTypical
Fig. 23 Check Engine LampÐXJ ModelsÐTypical
Fig. 24 Check Engine LampÐYJ ModelsÐTypical
14 - 28 FUEL SYSTEM COMPONENT DESCRIPTION/SYSTEM OPERATIONJ

line. However, these could result in a rich or lean
condition causing an oxygen sensor DTC to be stored
in the PCM.
Secondary Ignition Circuit:The PCM cannot
detect an inoperative ignition coil, fouled or worn
spark plugs, ignition cross firing, or open circuited
spark plug cables.
Engine Timing:The PCM cannot detect an incor-
rectly indexed timing chain, camshaft sprocket or
crankshaft sprocket. The PCM also cannot detect an
incorrectly indexed distributor. However, these could
result in a rich or lean condition causing an oxygen
sensor DTC to be stored in the PCM.
Cylinder Compression:The PCM cannot detect
uneven, low, or high engine cylinder compression.
Exhaust System:The PCM cannot detect a
plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions:The PCM cannot de-
termine if the fuel injector is clogged, or the wrong
injector is installed. However, these could result in a
rich or lean condition causing an oxygen sensor DTC
to be stored in the PCM.
Excessive Oil Consumption:Although the PCM
monitors exhaust stream oxygen content through ox-
ygen sensor (closed loop), it cannot determine exces-
sive oil consumption.
Throttle Body Air Flow:The PCM cannot detect
a clogged or restricted air cleaner inlet or air cleaner
element.
Evaporative System:The PCM will not detect a
restricted, plugged or loaded EVAP canister.
Vacuum Assist:Leaks or restrictions in the vac-
uum circuits of vacuum assisted engine control sys-
tem devices are not monitored by the PCM. However,
a vacuum leak at the MAP sensor will be monitored
and a diagnostic trouble code (DTC) will be gener-
ated by the PCM.
Powertrain Control Module (PCM) System
Ground:The PCM cannot determine a poor system
ground. However, a DTC may be generated as a re-
sult of this condition.
Powertrain Control Module (PCM) Connector
Engagement:The PCM cannot determine spread or
damaged connector pins. However, a DTC may be
generated as a result of this condition.
HIGH AND LOW LIMITS
The powertrain control module (PCM) compares in-
put signal voltages from each input device. It will es-
tablish high and low limits that are programmed into
it for that device. If the input voltage is not within
specifications and other Diagnostic Trouble Code
(DTC) criteria are met, a DTC will be stored in mem-
ory. Other DTC criteria might include engine rpm
limits or input voltages from other sensors or
switches. The other inputs might have to be sensed
by the PCM when it senses a high or low input volt-
age from the control system device in question.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored diagnostic trouble code (DTC) can be dis-
played by cycling the ignition key On-Off-On-Off-On
within three seconds and observing the malfunction
indicator lamp. This lamp is displayed on the instru-
ment panel as the CHECK ENGINE lamp (Figs. 45
or 46).
They can also be displayed through the use of the
Diagnostic Readout Box (DRB) scan tool. The DRB
scan tool connects to the data link connector in the
engine compartment (Figs. 47 or 48). For operation of
the DRB, refer to the appropriate Powertrain Diag-
nostic Procedures service manual.
Fig. 45 Check Engine LampÐXJ ModelsÐTypical
Fig. 46 Check Engine LampÐYJ ModelsÐTypical
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 53