2003 JEEP GRAND CHEROKEE Battery

outlet receptacle and a good ground. There should be
continuity. If OK, go to Step 4. If not OK, go to Step
5.
(4) Check for battery voltage at the insulated con-
tact located at the back of the power outlet recepta-
cle. If not OK, go to Step 5.
(5) Disconnect and isolate the battery negative
cable. Remove the instrument panel center lower
bezel. Check for continuity between the ground cir-
cuit cavity of the power outlet wire harness connector
and a good ground. There should be continuity. If
OK, go to Step 6. If not OK, repair the open ground
circuit to ground as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
power outlet wire harness connector. If OK, replace
the faulty power outlet receptacle. If not OK, repair
the open fused B(+) circuit to the junction block fuse
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the center lower bezel from the instru-
ment panel. Refer toInstrument Panel Center
Lower Bezelin Body for the procedure.
(3) Pull the cigar lighter knob and element or the
protective cap out of the cigar lighter receptacle base,
or open the power outlet door in the instrument
panel center lower bezel.
(4) Look inside the cigar lighter or power outlet
receptacle base and note the position of the rectangu-
lar retaining bosses of the mount that secures the
receptacle base to the instrument panel center lower
bezel (Fig. 15).
(5) Insert a pair of external snap ring pliers into
the cigar lighter or power outlet receptacle base and
engage the tips of the pliers with the retaining
bosses of the mount.
(6) Squeeze the pliers to disengage the mount
retaining bosses from the receptacle base and, using
a gentle rocking motion, pull the pliers and the
receptacle base out of the mount.
(7) Remove the cigar lighter or power outlet mount
from the instrument panel center lower bezel.
INSTALLATION
(1) Install the cigar lighter or power outlet mount
into the instrument panel center lower bezel.
(2) Align the splines on the outside of the cigar
lighter or power outlet receptacle base connector
receptacle with the grooves on the inside of the
mount.
(3) Press firmly on the cigar lighter or power out-
let receptacle base until the retaining bosses of the
mount are fully engaged in their receptacles.(4) Install the cigar lighter knob and element or
the protective cap into the cigar lighter receptacle
base, or close the power outlet door in the instrument
panel center lower bezel.
(5) Install the center lower bezel onto the instru-
ment panel. Refer toInstrument Panel Center
Lower Bezelin Body for the procedure.
(6) Reconnect the battery negative cable.
POWER OUTLET RELAY
DESCRIPTION
The power outlet / cigar lighter relay is an electro-
mechanical device that switches fused battery cur-
rent to the cigar lighter or power outlet when the
ignition switch is turned to the Accessory or On posi-
tions. The power outlet / cigar lighter relay is located
in the junction block, below the driver side of the
instrument panel in the passenger compartment.
The cigar lighter relay is a International Standards
Organization (ISO) relay. Relays conforming to the
ISO specifications have common physical dimensions,
current capacities, terminal patterns, and terminal
functions.
Fig. 15 Cigar Lighter and Power Outlet Remove/
Install - Typical
1 - KNOB AND ELEMENT
2 - RETAINING BOSSES-ENGAGE PLIERS HERE
3 - BASE
4 - PARTIALLY REMOVED
5 - EXTERNAL SNAP-RING PLIERS
6 - MOUNT
7 - BASE
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 13
POWER OUTLET (Continued)

The cigar lighter relay cannot be repaired or
adjusted and, if faulty or damaged, it must be
replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor or diode, and three (two fixed and one mov-
able) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts
(normally closed) by spring pressure. When the elec-
tromagnetic coil is energized, it draws the movable
contact away from the normally closed fixed contact,
and holds it against the other (normally open) fixed
contact.
When the electromagnetic coil is de-energized,
spring pressure returns the movable contact to the
normally closed position. The resistor or diode is con-
nected in parallel with the electromagnetic coil in the
relay, and helps to dissipate voltage spikes that are
produced when the coil is de-energized.
DIAGNOSIS AND TESTING - POWER OUTLET
RELAY
The power outlet / cigar lighter relay (Fig. 16) is
located in the junction block, below the driver side
end of the instrument panel in the passenger com-
partment. For complete circuit diagrams, refer to
Horn/Cigar Lighter/Power Outletin Wiring Dia-
grams.
WARNING: REFER TO RESTRAINTS BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Remove the power outlet / cigar lighter relay
from the junction block. Refer to the procedure in
this group.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, perform the Relay Circuit Test that
follows. If not OK, replace the faulty relay.
DIAGNOSIS AND TESTING - RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) of
the junction block is connected to battery voltage and
should be hot at all times. Check for battery voltage
at the fused B(+) circuit cavity in the junction block
receptacle for the cigar lighter relay. If OK, go to
Step 2. If not OK, repair the fused B(+) circuit to the
Power Distribution Center (PDC) fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the fused B(+) fuse in the junction block that feeds
the cigar lighter when the relay is energized by the
ignition switch. There should be continuity between
the junction block cavity for relay terminal 87 and
the fused B(+) fuse in the junction block at all times.
If OK, go to Step 4. If not OK, repair the open fused
B(+) circuit to the junction block fuse as required.
(4) The coil ground terminal (85) is connected to
the electromagnet in the relay. It receives battery
feed to energize the cigar lighter relay when the igni-
tion switch is in the Accessory or On positions. Turn
the ignition switch to the On position. Check for bat-
tery voltage at the fused ignition switch output (acc/
run) circuit cavity for relay terminal 85 in the
junction block receptacle for the cigar lighter relay. If
OK, go to Step 5. If not OK, repair the open fused
ignition switch output (acc/run) circuit to the ignition
switch as required.
(5) The coil battery terminal (86) is connected to
the electromagnet in the relay. The junction block
cavity for this terminal should have continuity to
Fig. 16 Accessory Relay
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
8W - 97 - 14 8W-97 POWER DISTRIBUTIONWJ
POWER OUTLET RELAY (Continued)

ground at all times. If not OK, repair the open
ground circuit to ground as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. Refer toSteering Col-
umn Opening Coverin Body for the procedure.
(3) The power outlet / cigar lighter relay is located
on the left side of the combination flasher in the
junction block.
(4) Remove the power outlet / cigar lighter relay
from the junction block.
INSTALLATION
(1) Position the power outlet / cigar lighter relay in
the proper receptacle in the junction block.
(2) Align the power outlet / cigar lighter relay ter-
minals with the terminal cavities in the junction
block receptacle.
(3) Push in firmly on the power outlet / cigar
lighter relay until the terminals are fully seated in
the terminal cavities in the junction block receptacle.
(4) Install the steering column opening cover onto
the instrument panel. Refer toSteering Column
Opening Coverin Body for the procedure.
(5) Reconnect the battery negative cable.
IOD WIRE HARNESS
CONNECTOR
DESCRIPTION
All vehicles are equipped with an Ignition-Off
Draw (IOD) connector that is located in a molded
connector receptacle on the lower rear surface of the
Junction Block (JB) housing (Fig. 17). The JB is con-
cealed above the molded plastic instrument panel
fuse cover. Integral latches molded into the fuse
cover secure it the JB, the Body Control Module
(BCM) and the 16-way data link connector tab of the
instrument panel steering column support bracket.
The fuse cover can be pulled downward to disengage
the latches and provide service access to all of the
fuses, relays and wire harness connectors of the JB.
Refer toInstrument Panel Fuse Coverin the
index of this service manual for the location of addi-
tional service information covering the fuse cover.
OPERATION
The term ignition-off draw identifies a normal con-
dition where power is being drained from the battery
with the ignition switch in the Off position. The IOD
connector feeds the memory and sleep mode func-
tions for some of the electronic modules in the vehicleas well as various other accessories that require bat-
tery current when the ignition switch is in the Off
position, including the clock.
The IOD connector can be used by the vehicle
owner as a convenient means of reducing battery
depletion when a vehicle is to be stored for periods
not to exceed about twenty days (short-term storage).
Simply disconnect the IOD connector from the JB
receptacle. However, it must be remembered that dis-
connecting the IOD connector will not eliminate IOD,
but only reduce this normal condition. When a vehi-
cle will not be used for more than twenty days, but
less than thirty days, remove the IOD fuse from the
Power Distribution Center (PDC). If a vehicle will be
stored for more than about thirty days, the battery
negative cable should be disconnected to eliminate
normal IOD; and, the battery should be tested and
recharged at regular intervals during the vehicle
storage period to prevent the battery from becoming
discharged or damaged. Refer toIgnition-Off Draw
Fig. 17 Ignition-Off Draw Connector
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 15
POWER OUTLET RELAY (Continued)

FuseandBatteryin the index in this service man-
ual for the location of additional service information
covering the ignition-off draw fuse and the battery.
FUSE COVER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Pull down on the rear edge (nearest the rear of
the vehicle) of the instrument panel fuse cover until
the rear latches unsnap from the tabs on the lower
junction block housing and the side latch unsnaps
from the tab on the instrument panel steering col-
umn support bracket outboard of the 16-way data
link connector (Fig. 18).
(3) Move the instrument panel fuse cover towards
the front of the vehicle to disengage the front latches
from the mounting slots in the lower housing of the
body control module.
(4) Remove the fuse cover from under the instru-
ment panel.
INSTALLATION
(1) Position the two front latches of the instrument
panel fuse cover within the two locator channel for-
mations on the bottom of the body control module
housing (Fig. 19).
(2) While applying a slight upward pressure to the
instrument panel fuse cover over the front latches,
slowly slide the front latches through the locator
channels toward the front of the vehicle until thelatches exit the front of the locator channels. This
will locate the front latches at the mounting slots in
the lower housing of the body control module.
(3) Apply a slight rearward pressure on the instru-
ment panel fuse cover to engage the front latches in
the mounting slots in the lower housing of the body
control module.
(4) Swing the rear edge (nearest the rear of the
vehicle) of the instrument panel fuse cover up toward
the junction block.
(5) Press firmly upward on the instrument panel
fuse cover over the rear latches until the latches
snap into place over the tabs on the lower edge of the
junction block housing.
(6) Press firmly upward on the 16-way data link
connector cover formation of the instrument panel
fuse cover until the side latch snaps into place over
the tab on the outboard side of the instrument panel
steering column support bracket.
(7) Reconnect the battery negative cable.
REAR POWER OUTLET
DESCRIPTION - REAR POWER OUTLET
A rear accessory power outlet is optional equip-
ment on this model. The rear power outlet is
installed in the lower right quarter trim panel near
the right liftgate opening pillar in the cargo area of
Fig. 18 Instrument Panel Fuse Cover Remove/Install
1 - REAR LATCHES
2 - JUNCTION BLOCK AND BODY CONTROL MODULE UNIT
3 - INSTRUMENT PANEL FUSE COVER
4 - SIDE LATCH
5 - FRONT LATCHES
Fig. 19 Instrument Panel Fuse Cover Locator
Channels
1 - JUNCTION BLOCK
2 - SCREWS (4)
3 - BODY CONTROL MODULE
4 - FUSE COVER LOCATOR CHANNELS
5 - FUSE COVER MOUNTING SLOTS
6 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
8W - 97 - 16 8W-97 POWER DISTRIBUTIONWJ
IOD WIRE HARNESS CONNECTOR (Continued)

the vehicle. The power outlet base and mount are
secured by a snap fit within the quarter trim panel.
A plastic protective cap snaps into the power outlet
base when the power outlet is not being used, and
hangs from the power outlet base mount by an inte-
gral bail strap while the power outlet is in use. While
the power outlet is very similar to a cigar lighter
base unit, it does not include the two small spring-
clip retainers inside the bottom of the receptacle
shell that are used to secure the cigar lighter heating
element to the insulated contact.
The power outlet receptacle unit and the accessory
power outlet protective cap are available for service.
The power outlet receptacle cannot be repaired and,
if faulty or damaged, it must be replaced.
OPERATION - REAR POWER OUTLET
The power outlet base or receptacle shell is con-
nected to ground, and an insulated contact in the
bottom of the shell is connected to battery current.
The power outlet receives battery voltage from a fuse
in the Power Distribution Center (PDC) through a
fuse in the Junction Block (JB) at all times. Refer to
Horn/Cigar Lighter/Power Outletin Wiring Dia-
grams for the location of complete rear power outlet
circuit diagrams.
DIAGNOSIS AND TESTING - REAR POWER
OUTLET
Refer toHorn/Cigar Lighter/Power Outletin
Wiring Diagrams for the location of complete rear
power outlet circuit diagrams.
(1) Check the fused B(+) fuse in the Junction
Block (JB). If OK, go to Step 2. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the JB. If OK, go to Step 3. If not OK, repair the
open fused B(+) circuit to the Power Distribution
Center (PDC) as required.
(3) Remove the plastic protective cap from the rear
power outlet receptacle. Check for continuity between
the inside circumference of the rear power outlet
receptacle and a good ground. There should be conti-
nuity. If OK, go to Step 4. If not OK, go to Step 5.
(4) Check for battery voltage at the insulated con-
tact located at the back of the rear power outlet
receptacle. If not OK, go to Step 5.(5) Disconnect and isolate the battery negative
cable. Remove the rear power outlet from the right
quarter trim panel. Check for continuity between the
ground circuit cavity of the rear power outlet wire
harness connector and a good ground. There should
be continuity. If OK, go to Step 6. If not OK, repair
the open ground circuit to ground as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
rear power outlet wire harness connector. If OK,
replace the faulty rear power outlet receptacle base.
If not OK, repair the open fused B(+) circuit to the
JB fuse as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Pull the protective cap out of the rear power
outlet receptacle base (Fig. 20).
Fig. 20 Rear Power Outlet Remove/Install
1 - RIGHT QUARTER TRIM PANEL
2 - RIGHT BODY WIRE HARNESS CONNECTOR
3 - RECEPTACLE BASE
4 - PROTECTIVE CAP
5 - MOUNT
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 17
REAR POWER OUTLET (Continued)

(3) Look inside the rear power outlet receptacle
base and note the position of the rectangular retain-
ing bosses of the mount that secures the receptacle
base to the right quarter trim panel (Fig. 21).(4) Insert a pair of external snap ring pliers into
the rear power outlet receptacle base and engage the
tips of the pliers with the retaining bosses of the
mount.
(5) Squeeze the pliers to disengage the mount
retaining bosses from the receptacle base and, using
a gentle rocking motion, pull the pliers and the
receptacle base out of the mount.
(6) Pull the rear power outlet receptacle base away
from the right quarter trim panel far enough to
access the wire harness connector.
(7) Disconnect the right body wire harness connec-
tor from the rear power outlet receptacle base con-
nector receptacle.
(8) Remove the rear power outlet mount from the
right quarter trim panel.
INSTALLATION
(1) Align the splines on the outside of the rear
power outlet receptacle base connector receptacle
with the grooves on the inside of the mount.
(2) Insert the rear power outlet receptacle base
about half way through the mount.
(3) Reconnect the right body wire harness connec-
tor to the rear power outlet receptacle base connector
receptacle.
(4) Insert the rear power outlet receptacle base
and mount into the right quarter trim panel as a
unit until the mount is seated flush against the trim
panel.
(5) Press firmly on the rear power outlet receptacle
base until the retaining bosses of the mount are fully
engaged in their receptacles.
(6) Install the protective cap into the rear power
outlet receptacle base.
(7) Reconnect the battery negative cable.
Fig. 21 Power Outlet Remove/Install - Typical
1 - KNOB AND ELEMENT
2 - RETAINING BOSSES-ENGAGE PLIERS HERE
3 - BASE
4 - PARTIALLY REMOVED
5 - EXTERNAL SNAP-RING PLIERS
6 - MOUNT
7 - BASE
8W - 97 - 18 8W-97 POWER DISTRIBUTIONWJ
REAR POWER OUTLET (Continued)

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
ENGINE PERFORMANCE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or dead battery 1. Charge/Replace Battery. (Refer to
8 - ELECTRICAL/BATTERY
SYSTEM/BATTERY - STANDARD
PROCEDURE), for correct
procedures. Check charging system.
(Refer to 8 - ELECTRICAL/
CHARGING - DIAGNOSIS AND
TESTING), for correct procedures.
2. Corroded or loose battery
connections2. Clean/tighten suspect battery/
starter connections
3. Faulty starter or related circuit(s) 3. Check starting system. (Refer to 8
- ELECTRICAL/STARTING -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
4. Siezed accessory drive
component4. Remove accessory drive belt and
attempt to start engine. If engine
starts, repair/replace siezed
component.
5. Engine internal mechanical failure
or hydro-static lock5. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
ENGINE CRANKS BUT WILL
NOT START1. No spark 1. Check for spark. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL -
SPECIFICATIONS), for correct
procedures.
2. No fuel 2. Perform fuel pressure test (Refer
to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING), and if
necessary, inspect fuel injector(s) and
driver circuits. (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL
INJECTOR - DIAGNOSIS AND
TESTING), for correct procedures.
3. Low or no engine compression 3. Perform cylinder compression
pressure test. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
ENGINE LOSS OF POWER 1. Worn or burned distributor rotor 1. Install new distributor rotor
2. Worn camshaft position sensor
shaft2. Remove and repair camshaft
position sensor.(Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
CAMSHAFT POSITION SENSOR -
REMOVAL).
9 - 4 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing)
²Leaks between adjacent cylinders or into water
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn OFF the
engine.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or oil filler cap opening.
Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder CYLINDER COMBUSTION
PRESSURE LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 8 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)