2003 JEEP GRAND CHEROKEE Pin outs

(5) Remove the door cylinder lock switch from the
back of the lock cylinder.
INSTALLATION
(1) Position the door cylinder lock switch onto the
back of the lock cylinder with its pigtail wire harness
oriented toward the bottom (Fig. 2).
(2) Position the lock lever onto the pin on the back
of the door lock cylinder with the lever oriented
toward the rear.
(3) Install the retainer clip onto the pin on the
back of the door lock cylinder. Be certain that the
center tab of the retainer is engaged in the retention
hole on the lock lever.
(4) Reinstall the outside door handle unit onto the
outer door panel. (Refer to 23 - BODY/DOOR -
FRONT/EXTERIOR HANDLE - INSTALLATION).
(5) Reconnect the battery negative cable.
HOOD AJAR SWITCH
DESCRIPTION
The hood ajar switch is a self-adjusting, normally
closed, single pole, double throw momentary switch
that is used only on vehicles built for sale in certain
international markets where it is required equipment
(Fig. 3). The mounting bracket is fastened to the left
inner fender. A molded plastic striker with three inte-
gral retainers is secured to the underside of the hood
panel inner reinforcement to actuate the switch
plunger as the hood panel is closed.The switchreceives a path to ground through the left inner
fender shield in the engine compartment.
The hood ajar switch adjusts itself as the striker
pushes the switch body down through the switch
when the hood panel is closed after the initial instal-
lation. This self-adjustment feature is only functional
the first time the hood is closed following installa-
tion. If the switch requires adjustment following the
initial installation, the switch must be replaced.
OPERATION
The normally closed hood ajar switch is normally
held open when the hood panel is closed and latched.
When the hood is opened, the switch plunger extends
from the switch body and the switch contacts are
closed. The hood ajar switch is connected in series
between ground and the hood ajar switch sense input
of the Body Control Module (BCM). The BCM uses
an internal resistor pull up to monitor the state of
the hood ajar switch contacts. The hood ajar switch
can be diagnosed using conventional diagnostic tools
and methods.
DIAGNOSIS AND TESTING - HOOD AJAR
SWITCH
The diagnosis found here addresses an inoperative
hood ajar switch. If the problem being diagnosed is
related to hood ajar switch accuracy, be certain to
confirm that the problem is not an improperly
adjusted hood ajar switch. If no hood ajar switch
adjustment problem is found, the following procedure
will help to locate a short or open in the hood ajar
switch circuit. Refer to the appropriate wiring infor-
mation.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Disconnect the hood ajar switch. Check for
continuity between the harness ground circuit a good
ground. There should be continuity. If OK, go to Step
2. If not OK, repair the open ground circuit to
ground.
Fig. 3 Hood Ajar Switch
1 - SWITCH
2 - STUD (2)
3 - BRACKET
4 - FENDER
5 - CONNECTOR
6 - NUT (2)
WJVEHICLE THEFT SECURITY 8Q - 9
DOOR CYLINDER LOCK SWITCH (Continued)

WASHER SYSTEM
The washer system components should be
inspected periodically, not just when washer perfor-
mance problems are experienced. This inspection
should include the following points:
(1) Check for ice or other foreign material in the
washer reservoir. If contaminated, clean and flush
the washer system. (Refer to 8 - ELECTRICAL/
FRONT WIPERS/WASHERS - CLEANING).
(2) Inspect the washer plumbing for pinched, leak-
ing, deteriorated, or incorrectly routed hoses and
damaged or disconnected hose fittings. Replace dam-
aged or deteriorated hoses and hose fittings. Leaking
washer hoses can sometimes be repaired by cutting
the hose at the leak and splicing it back together
using an in-line connector fitting. Similarly, sections
of deteriorated hose can be cut out and replaced by
splicing in new sections of hose using in-line connec-
tor fittings. Whenever routing a washer hose or a
wire harness containing a washer hose, it must be
routed away from hot, sharp, or moving parts. Also,
sharp bends that might pinch the washer hose must
be avoided.
FRONT CHECK VALVE
DESCRIPTION
A front washer system check valve is standard
equipment on this model. The front check valve is
integral to the front washer nozzle plumbing wye fit-
ting located in the cowl plenum beneath the cowl ple-
num cover/grille panel near the base of the
windshield. The check valve consists of a molded
plastic body with a round center section. Three
barbed hose nipples are formed in a wye configura-
tion on the outside circumference of the center sec-
tion of the valve body. Within the check valve body, a
small check valve operated by a small coiled spring
restricts flow through the unit until the valve is
unseated by a predetermined inlet fluid pressure.
The front check valve cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The front check valve provides more than one func-
tion in this application. It serves as a wye connector
fitting between the cowl grille panel and washer noz-
zle sections of the front washer supply hose. It also
prevents washer fluid from draining out of the front
washer supply hoses back to the washer reservoir.
This drain-back would result in a lengthy delay from
when the front washer switch is actuated until
washer fluid was dispensed through the front washer
nozzles, because the front washer pump would have
to refill the front washer plumbing from the reservoir
to the nozzles. Finally, the front check valve prevents
washer fluid from siphoning through the front
washer nozzles after the front washer system is
turned Off. When the front washer pump pressurizes
and pumps washer fluid from the reservoir through
the front washer plumbing, the fluid pressure over-
rides the spring pressure applied to the check valve
and unseats the valve, allowing washer fluid to flow
toward the front washer nozzles. When the front
washer pump stops operating, spring pressure seats
the check valve and fluid flow in either direction
within the front washer plumbing is prevented.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - REMOVAL).
(3) Open the hood and pull the hood to plenum
seal off of the forward flanges of the cowl grille cover
and the plenum panel.
Fig. 2 Wiper Blade Inspection
1 - WORN OR UNEVEN EDGES
2 - ROAD FILM OR FOREIGN MATERIAL DEPOSITS
3 - HARD, BRITTLE, OR CRACKED
4 - DEFORMED OR FATIGUED
5 - SPLIT
6 - DAMAGED SUPPORT COMPONENTS
WJFRONT WIPERS/WASHERS 8R - 9
FRONT WIPERS/WASHERS (Continued)

Washer hose is available for service only as roll
stock, which must then be cut to length. The molded
plastic washer hose fittings cannot be repaired. If
these fittings are faulty or damaged, they must be
replaced.
OPERATION
Washer fluid in the washer reservoir is pressurized
and fed by the front washer pump/motor through the
front washer system plumbing and fittings to the two
front washer nozzles. Whenever routing the washer
hose or a wire harness containing a washer hose, it
must be routed away from hot, sharp, or moving
parts; and, sharp bends that might pinch the hose
must be avoided.
FRONT WASHER NOZZLE
DESCRIPTION
The two front washer nozzles have integral snap
features that secure them in dedicated holes in the
cowl plenum cover/grille panel located near the base
of the windshield. The domed upper surface of the
washer nozzle is visible on the top of the plenum cov-
er/grille panel, and the nozzle orifice is oriented
towards the windshield glass. The washer plumbing
fittings for the washer nozzles are concealed beneath
the cowl plenum cover/grille panel. These fluidic
washer nozzles are constructed of molded plastic. The
cowl plenum cover/grille panel must be removed from
the vehicle to access the nozzles for service. The
washer nozzles cannot be adjusted or repaired. If
faulty or damaged, they must be replaced.
OPERATION
The two front washer nozzles are designed to dis-
pense washer fluid into the wiper pattern area on the
outside of the windshield glass. Pressurized washer
fluid is fed to each nozzle from the washer reservoir
by the front washer pump/motor through a single
hose, which is attached to a barbed nipple on each
front washer nozzle below the cowl plenum cover/
grille panel. The washer nozzles incorporate a fluidic
design, which causes the nozzle to emit the pressur-
ized washer fluid as an oscillating stream to more
effectively cover a larger area of the glass area to be
cleaned.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - REMOVAL).
(3) Unlatch and open the hood.(4) Pull the hood to plenum seal off of the forward
flanges of the cowl grille cover and the plenum panel.
(5) Remove the six plastic nuts (2 short and 4
long) that secure the cowl grille cover to the studs on
the cowl top panel near the base of the windshield
(Fig. 4).
(6) Lift the left end of the cowl grille cover off of
the cowl plenum panel far enough to access the front
washer plumbing.
(7) Disconnect the engine compartment washer
hose from the cowl grille cover washer hose at the
plastic elbow connector.
(8) Remove the cowl grille cover from the cowl ple-
num and cowl top panels through the opening
between the hood and the base of the windshield.
(9) From the underside of the cowl grille cover, dis-
connect the washer hose(s) from the barbed nipple(s)
of the front washer nozzle(s).
(10) From the underside of the cowl grille cover,
release the integral snap features of the front washer
nozzle(s) and push the nozzle(s) out through the
mounting hole toward the top side of the cowl grille
cover.
INSTALLATION
(1) From the top side of the cowl grille cover,
insert the nipple end of the front washer nozzle(s)
through the mounting hole in the cowl grille cover.
(2) Push firmly and evenly on the top of the front
washer nozzle until the integral snap features lock
into place on the underside of the cowl grille cover.
(3) From the underside of the cowl grille cover,
reconnect the washer hose(s) to the barbed nipple(s)
of the front washer nozzle(s).
Fig. 4 Cowl Grille Cover Remove/Install
1 - WASHER HOSE CONNECTION
2 - STUDS (6)
3 - COWL GRILLE COVER
4 - PLASTIC NUT (6)
WJFRONT WIPERS/WASHERS 8R - 11
FRONT WASHER HOSES/TUBES (Continued)

(9) Install the six plastic nuts that secure the cowl
grille cover to the studs on the cowl top panel near
the base of the windshield. These nuts are to be
installed by pushing them onto the studs in the fol-
lowing sequence:
(a) First, install the short nuts to the third stud
from the right, then the second stud from the left.
(b) Next, install long nuts to the right outboard
stud, then the left outboard stud.
(c) Finally, install the two remaining long nuts
to the third stud from the left, then the second
stud from the right.
(10) Starting at the ends and working toward the
center, push the hood to plenum seal onto the for-
ward flanges of the cowl grille cover and the plenum
panel.
(11) Close and latch the hood.
(12) Reinstall the wiper arms onto the wiper piv-
ots. (Refer to 8 - ELECTRICAL/FRONT WIPERS/
WASHERS/FRONT WIPER ARMS -
INSTALLATION).
(13) Reconnect the battery negative cable.
RAIN SENSOR MODULE
DESCRIPTION
The Rain Sensor Module (RSM) is the primary
component of the automatic wiper system (Fig. 14).
The RSM is located on the inside of the windshield,
between the rear view mirror mounting button and
the windshield header and is concealed behind a
molded plastic trim cover that snaps over the modulehousing. The triangular-shaped molded black plastic
housing of the RSM has a rectangular opening
located on the upper end of the housing for the mod-
ule connector receptacle, which contains four termi-
nal pins. These terminal pins connect the rain sensor
to the vehicle electrical system through a dedicated
take out and connector of the overhead wire harness
that extends from above the headliner. Five openings
on the windshield side of the RSM housing are fitted
with eight convex clear plastic lenses. A metal spring
clip on each side of the housing near the bottom
secures the RSM to a plastic mounting bracket that
is bonded to the windshield glass. Concealed within
the RSM housing is the electronic circuitry of the
module, which includes four InfraRed (IR) diodes,
two photocells, and a microprocessor.
The RSM software is Flash compatible, which
means it can be reprogrammed using Flash repro-
gramming procedures. However, if any of the hard-
ware of the RSM is damaged or faulty, the entire
module must be replaced. The RSM bracket is ser-
viced as a unit with the windshield glass. If the
bracket is faulty, damaged, or separated from the
windshield glass, the windshield unit must be
replaced.
OPERATION
The microprocessor-based Rain Sensor Module
(RSM) senses moisture in the wipe pattern on the
outside of the windshield glass and sends wipe com-
mands to the Body Control Module (BCM). Four
InfraRed (IR) diodes within the RSM generate IR
light beams that are aimed by four of the convex
optical lenses near the base of the module through
the windshield glass. Four additional convex optical
lenses near the top of the RSM are focused on the IR
light beams on the outside of the windshield glass
and allow the two photocells within the module to
sense changes in the intensity of these IR light
beams. When sufficient moisture accumulates within
the wipe pattern of the windshield glass, the RSM
detects a change in the monitored IR light beam
intensity.
The internal programming of the RSM then sends
the appropriate electronic wipe command messages
to the BCM over the Programmable Communications
Interface (PCI) data bus. The BCM responds by acti-
vating or deactivating the front wiper system. The
BCM also sends electronic sensitivity level messages
to the RSM over the PCI data bus based upon the
driver-selected sensitivity setting of the control knob
on the control stalk of the right (wiper) multi-func-
tion switch. The higher the selected sensitivity set-
ting the more sensitive the RSM is to the
accumulated moisture on the windshield glass, and
Fig. 14 Rain Sensor Module
1 - SPRING CLIP (2)
2 - INFRARED LENS (4)
3 - HOUSING
4 - CONNECTOR RECEPTACLE
5 - PHOTOCELL LENS (4)
8R - 18 FRONT WIPERS/WASHERSWJ
FRONT WIPER MODULE (Continued)

²Washer Reservoir- The rear washer system
shares a single reservoir with the front washer sys-
tem, but has its own dedicated washer pump/motor
and plumbing. The washer reservoir is concealed
between the left inner fender shield and the left
outer fender panel, behind the inner fender liner and
ahead of the left front wheel. The washer reservoir
filler neck is the only visible portion of the reservoir,
and it is accessed from the left front corner of the
engine compartment.
Features of the rear wiper and washer system
include the following:
²Continuous Wipe Mode- When the right
multi-function switch control sleeve is moved to the
On position, the rear wiper will be operated at a
fixed speed, continual wipe cycle until the switch
sleeve is moved to the Delay or Off positions, until
the ignition switch is turned to the Off position, or
until the liftgate flip-up glass is ajar.
²Intermittent Wipe Mode- When the right
multi-function switch control sleeve is moved to the
Delay position, the rear wiper will be operated in a
fixed interval, intermittent wipe cycle until the
switch sleeve is moved to the On or Off positions,
until the ignition switch is turned to the Off position,
until the liftgate flip-up glass is ajar, or until the
right multi-function switch control stalk is pushed
forward to activate the rear washer system. The
intermittent wipe mode delay time has a fixed delay
interval of about five to eight seconds between
sweeps.
²Washer Mode- When the right multi-function
switch control stalk is pushed forward to activate the
rear washer system, washer fluid will be dispensed
from the washer reservoir onto the liftgate glass
through the rear washer nozzle and the rear wiper
will operate in a fixed cycle (not intermittent) for as
long as the rear washer pump/motor unit remains
energized. When the control stalk is released from
the momentary Wash position, the wipe-after-wash
feature will continue to operate the rear wiper at a
fixed cycle for about three additional wiper sweeps
before returning to the previously selected mode.
Hard wired circuitry connects the rear wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the rear wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repairprocedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATION
The rear wiper and washer system is intended to
provide the vehicle operator with a convenient, safe,
and reliable means of maintaining visibility through
the liftgate glass. The various components of this sys-
tem are designed to convert electrical energy pro-
duced by the vehicle electrical system into the
mechanical action of the wiper blade to wipe the out-
side surface of the glass, as well as into the hydraulic
action of the washer system to apply washer fluid
stored in an on-board reservoir to the area of the
glass to be wiped. When combined, these components
provide the means to effectively maintain clear visi-
bility for the vehicle operator by removing excess
accumulations of rain, snow, bugs, mud, or other
minor debris from the outside liftgate glass surface
that might be encountered while driving the vehicle
under numerous types of inclement operating condi-
tions. The vehicle operator initiates all rear wiper
and washer system functions with the right multi-
function switch located on the right side of the steer-
ing column, just below the steering wheel. Moving
the switch control sleeve to a detent position selects
the rear wiper system operating mode. Moving the
switch control stalk forward to a momentary position
activates the rear washer pump/motor, which dis-
penses washer fluid onto the liftgate glass through
the rear washer nozzle and operates the rear wiper
system in the fixed cycle mode for as long as the
washer switch is closed plus about three wiper
sweeps.
When the ignition switch is in the Accessory or On
positions, battery current from a fuse in the Junction
Block (JB) is provided to the right multi-function
switch through a fused ignition switch output (run-
acc) circuit. A separate fuse in the JB provides bat-
tery current to the electronic control circuitry of the
rear wiper module through a fused B(+) circuit.
When the right multi-function switch control sleeve
On position is selected, the On position circuitry
within the switch directs a battery current rear
wiper motor control signal input to the rear wiper
module electronic circuitry, which causes the rear
wiper motor to run at a fixed continuous wipe cycle.
When the right multi-function switch control sleeve
Delay position is selected, the Delay position cir-
cuitry within the switch directs a battery current
rear washer switch output signal input to the rear
wiper module electronic circuitry, which causes the
rear wiper motor to run at a fixed intermittent wipe
cycle. When the right multi-function switch control
8R - 34 REAR WIPERS/WASHERSWJ
REAR WIPERS/WASHERS (Continued)

motor that is secured with screws to the wiper motor
and to the liftgate inner panel.
²Electronic Controls- The rear wiper module
electronic controls include the rear wiper system
electronic logic and rear wiper motor electronic con-
trols. The electronic controls for the motor include an
electronic speed control that speeds the wiper blade
near the center of the glass, but slows the wiper
blade during directional reversals at each end of the
wipe pattern and during wiper blade off-the-glass
parking for quieter operation.
²Motor- The permanent magnet rear wiper
motor is secured with screws to the rear wiper mod-
ule bracket. The wiper motor includes an integral
transmission, and the motor output shaft.
The rear wiper module cannot be adjusted or
repaired. If any component of the module is faulty or
damaged, the entire rear wiper module unit must be
replaced. The motor output shaft gasket, bezel, nut,
and nut cover are available for service replacement.
OPERATION
The rear wiper module receives non-switched bat-
tery current through a fuse in the Junction Block
(JB) and is grounded at all times. The rear wiper
module operation is controlled by the vehicle operator
through battery current signal inputs received by the
rear wiper module electronic controls from the right
multi-function switch on the steering column. The
module also receives an external control input from
the liftgate flip-up glass ajar switch circuit. The rear
wiper module electronic control logic uses these
inputs, its internal inputs, and its programming to
provide continuous wipe, delay wipe, wipe-after-wash
and off-the-glass wiper blade parking. The wiper
blade cycling is controlled by the rear wiper module
electronic controls, which control current flow to the
wiper motor brushes. The wiper motor transmission
converts the rotary output of the wiper motor to the
back and forth wiping motion of the rear wiper arm
and blade on the liftgate glass.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the rear wiper arm from the rear
wiper motor output shaft. (Refer to 8 - ELECTRI-
CAL/REAR WIPERS/WASHERS/REAR WIPER ARM
- REMOVAL).
(3) Use a door trim panel removal tool to gently
pry at the base of the nut cover where it meets the
wiper motor output shaft bezel and gasket on the
outer liftgate panel until it unsnaps from the bezel
(Fig. 13). Be certain to use proper caution to protect
the outer liftgate panel and its paint finish from
damage during this procedure.(4) Remove the nut that secures the rear wiper
motor output shaft to the outer liftgate panel.
(5) Remove the bezel and gasket from the rear
wiper motor output shaft.
(6) Remove the trim panel from the inside of the
liftgate. (Refer to 23 - BODY/DECKLID/HATCH/
LIFTGATE/TAILGATE/TRIM PANEL - REMOVAL).
(7) Disconnect the liftgate wire harness connector
for the rear wiper module from the module connector
receptacle (Fig. 14).
(8) Loosen the two nuts that secure the rear wiper
module mounting bracket to the liftgate inner panel.
(9) Slide the rear wiper module and mounting
bracket forward far enough to disengage the mount-
ing nuts from the keyed holes in the liftgate inner
panel.
(10) Remove the rear wiper module and mounting
bracket from the liftgate as a unit.
INSTALLATION
(1) Position the rear wiper module and bracket to
the liftgate as a unit (Fig. 14).
(2) Insert the rear wiper motor output shaft
through the hole in the liftgate outer panel and
engage the mounting nuts in the keyed holes in the
liftgate inner panel.
(3) From the outside of the liftgate, center the rear
wiper motor output shaft in the liftgate outer panel
mounting hole and install the gasket and bezel over
the centered shaft (Fig. 13).
Fig. 13 Rear Wiper Motor Output Shaft Remove/
Install
1 - NUT
2 - NUT COVER
3 - BEZEL AND GASKET
4 - LIFTGATE OUTER PANEL
5 - REAR WIPER MOTOR OUTPUT SHAFT
WJREAR WIPERS/WASHERS 8R - 45
REAR WIPER MODULE (Continued)

DESCRIPTION - CIRCUIT FUNCTIONS
All circuits in the diagrams use an alpha/numeric
code to identify the wire and it's function. To identify
which circuit code applies to a system, refer to the
Circuit Identification Code Chart. This chart shows
the main circuits only and does not show the second-
ary codes that may apply to some models.
CIRCUIT IDENTIFICATION CODE CHART
CIRCUIT FUNCTION
A BATTERY FEED
B BRAKE CONTROLS
C CLIMATE CONTROLS
D DIAGNOSTIC CIRCUITS
E DIMMING ILLUMINATION
CIRCUITS
F FUSED CIRCUITS
G MONITORING CIRCUITS
(GAUGES)
H OPEN
I NOT USED
J OPEN
K POWERTRAIN CONTROL
MODULE
L EXTERIOR LIGHTING
M INTERIOR LIGHTING
N NOT USED
O NOT USED
P POWER OPTION (BATTERY
FEED)
Q POWER OPTIONS (IGNITION
FEED)
R PASSIVE RESTRAINT
S SUSPENSION/STEERING
T TRANSMISSION/TRANSAXLE/
TRANSFER CASE
U OPEN
V SPEED CONTROL, WIPER/
WASHER
W OPEN
X AUDIO SYSTEMS
Y OPEN
Z GROUNDS
DESCRIPTION - SECTION IDENTIFICATION AND
INFORMATION
The wiring diagrams are grouped into individual
sections. If a component is most likely found in a par-
ticular group, it will be shown complete (all wires,
connectors, and pins) within that group. For exam-
ple, the Auto Shutdown Relay is most likely to be
found in Group 30, so it is shown there complete. It
can, however, be shown partially in another group if
it contains some associated wiring.
Splice diagrams in Section 8W-70 show the entire
splice and provide references to other sections the
splices serves. Section 8W-70 only contains splice dia-
grams that are not shown in their entirety some-
where else in the wiring diagrams.
Section 8W-80 shows each connector and the cir-
cuits involved with that connector. The connectors
are identified using the name/number on the dia-
gram pages.
WIRING SECTION CHART
GROUP TOPIC
8W-01 thru
8W-09General information and Diagram
Overview
8W-10 thru
8W-19Main Sources of Power and
Vehicle Grounding
8W-20 thru
8W-29Starting and Charging
8W-30 thru
8W-39Powertrain/Drivetrain Systems
8W-40 thru
8W-49Body Electrical items and A/C
8W-50 thru
8W-59Exterior Lighting, Wipers and
Trailer Tow
8W-60 thru
8W-69Power Accessories
8W-70 Splice Information
8W-80 Connector Pin Outs
8W-91 Connector, Ground and Splice
Locations
8W - 01 - 6 8W-01 WIRING DIAGRAM INFORMATIONWJ
WIRING DIAGRAM INFORMATION (Continued)

It is not necessary to charge the tappets with
engine oil. They will charge themselves within a very
short period of engine operation.
(1) Dip each tappet in MopartEngine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool to install each tappet in the same bore from
where it was originally removed.
(3) Install the cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
(4) Install the push rods in their original locations.
(5) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(6) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 N´m (21 ft. lbs.) torque.
(7)
Pour the remaining MopartEngine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The MopartEngine Oil Supplement, or equiv-
alent must remain with the engine oil for at least 1 609
km (1,000 miles). The oil supplement need not be
drained until the next scheduled oil change.
(8) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
PISTON & CONNECTING ROD
DESCRIPTION
The pistons (Fig. 55) are made of a high strength
aluminum alloy, the piston skirts are coated with a
solid lubricant (Molykote) to reduce friction and pro-
vide scuff resistance. The connecting rods are made
of cast iron.
STANDARD PROCEDURE - PISTON FITTING
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, capable of reading in 0.003 mm
(.0001 in.) INCREMENTS is required. If a bore
gauge is not available, do not use an inside microme-
ter.
(2) Measure the inside diameter of the cylinder
bore at a point 49.5 mm (1-15/16 inches) below top of
bore. Start perpendicular (across or at 90 degrees) to
the axis of the crankshaft at point A and then take
an additional bore reading 90 degrees to that at point
B (Fig. 57).
(3) The coated pistons will be serviced with the
piston pin and connecting rod pre-assembled.The
coated piston connecting rod assembly can be
used to service previous built engines and
MUST be replaced as complete sets.Tin coated
pistons should not be used as replacements for coated
pistons.
(4) The coating material is applied to the piston
after the final piston machining process. Measuring
the outside diameter of a coated piston will not pro-
vide accurate results (Fig. 56). Therefore measuring
the inside diameter of the cylinder bore with a dial
Bore Gauge isMANDATORY. To correctly select the
proper size piston, a cylinder bore gauge capable of
reading in 0.003 mm (.0001 in.) increments is
required.
(5) Piston installation into the cylinder bore
requires slightly more pressure than that required
for non-coated pistons. The bonded coating on the
piston will give the appearance of a line-to-line fit
with the cylinder bore.
Fig. 55 Piston and Connecting Rod Assembly
Fig. 56 Moly Coated Piston
1 - MOLY COATED
2 - MOLY COATED
9 - 44 ENGINE - 4.0LWJ
HYDRAULIC LIFTERS (Continued)