2002 JEEP GRAND CHEROKEE Wire

(2) Disconnect and isolate the battery negative
cable. Connect the battery charger leads. Some bat-
tery chargers are equipped with polarity-sensing cir-
cuitry. This circuitry protects the battery charger and
the battery from being damaged if they are improp-
erly connected. If the battery state-of-charge is too
low for the polarity-sensing circuitry to detect, the
battery charger will not operate. This makes it
appear that the battery will not accept charging cur-
rent. See the instructions provided by the manufac-
turer of the battery charger for details on how to
bypass the polarity-sensing circuitry.
(3) Battery chargers vary in the amount of voltage
and current they provide. The amount of time
required for a battery to accept measurable charging
current at various voltages is shown in the Charge
Rate Table. If the charging current is still not mea-
surable at the end of the charging time, the battery
is faulty and must be replaced. If the charging cur-
rent is measurable during the charging time, the bat-
tery may be good and the charging should be
completed in the normal manner.
CHARGE RATE TABLE
Voltage Hours
16.0 volts maximum up to 4 hours
14.0 to 15.9 volts up to 8 hours
13.9 volts or less up to 16 hours
CHARGING TIME REQUIRED
The time required to charge a battery will vary,
depending upon the following factors:
²Battery Capacity- A completely discharged
heavy-duty battery requires twice the charging time
of a small capacity battery.
²Temperature- A longer time will be needed to
charge a battery at -18É C (0É F) than at 27É C (80É
F). When a fast battery charger is connected to a cold
battery, the current accepted by the battery will bevery low at first. As the battery warms, it will accept
a higher charging current rate (amperage).
²Charger Capacity- A battery charger that
supplies only five amperes will require a longer
charging time. A battery charger that supplies
twenty amperes or more will require a shorter charg-
ing time.
²State-Of-Charge- A completely discharged bat-
tery requires more charging time than a partially
discharged battery. Electrolyte is nearly pure water
in a completely discharged battery. At first, the
charging current (amperage) will be low. As the bat-
tery charges, the specific gravity of the electrolyte
will gradually rise.
The Battery Charging Time Table gives an indica-
tion of the time required to charge a typical battery
at room temperature based upon the battery state-of-
charge and the charger capacity.
BATTERY CHARGING TIME TABLE
Charging
Amperage5 Amps10
Amps20 Amps
Open Circuit
VoltageHours Charging @ 21É C (70É
F)
12.25 to 12.49 6 hours 3 hours 1.5
hours
12.00 to 12.24 10 hours 5 hours 2.5
hours
10.00 to 11.99 14 hours 7 hours 3.5
hours
Below 10.00 18 hours 9 hours 4.5
hours
STANDARD PROCEDURE - USING MICRO 420
ELECTRICAL TESTER
Always use the Micro 420 Instruction Manual that
was supplied with the tester as a reference. If the
Instruction Manual is not available the following pro-
cedure can be used:
WARNING: ALWAYS WEAR APPROPRIATE EYE
PROTECTION AND USE EXTREME CAUTION WHEN
WORKING WITH BATTERIES.
BATTERY TESTING
(1) If testing the battery OUT-OF-VEHICLE, clean
the battery terminals with a wire brush before test-
ing. If the battery is equipped with side post termi-
nals, install and tighten the supplied lead terminal
stud adapters. Do not use steel bolts. Failure to prop-
erly install the stud adapters, or using stud adapters
that are dirty or worn-out may result in false test
readings.
Fig. 5 Voltmeter - Typical
8F - 10 BATTERY SYSTEMWJ
BATTERY (Continued)

STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to thirty-five milliamperes (0.005 to 0.035 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. Up to thirty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.
If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IODIOD After Time
Out
Radio No1to3
milliamperesN/A
Audio Power
AmplifierNoup to 1
milliampereN/A
Body Control Module
(BCM)No5.90
milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
Transmission Control
Module (TCM) 4.7L
w/45RFEYES (20 minutes, ignition on) 130 milliamperes 0.64 milliampere
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Determine that the underhood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up tothree minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
WJBATTERY SYSTEM 8F - 13
BATTERY (Continued)

(5) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Power Distribution Center (PDC) and
then in the Junction Block (JB), one at a time until
the amperage reading becomes very low, or nonexist-
ent. Refer to the appropriate wiring information in
this service manual for complete PDC and JB fuse,
circuit breaker, and circuit identification. This will
isolate each circuit and identify the circuit that is the
source of the high-amperage IOD. If the amperage
reading remains high after removing and replacing
each fuse and circuit breaker, disconnect the wire
harness from the generator. If the amperage reading
now becomes very low or nonexistent, refer to Charg-
ing System for the proper charging system diagnosis
and testing procedures. After the high-amperage IOD
has been corrected, switch the multi-meter to pro-
gressively lower amperage scales and, if necessary,
repeat the fuse and circuit breaker remove-and-re-
place process to identify and correct all sources of
excessive IOD. It is now safe to select the lowest mil-
liampere scale of the multi-meter to check the low-
amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(6) Observe the multi-meter reading. The low-am-
perage IOD should not exceed thirty-five milliam-
peres (0.035 ampere). If the current draw exceeds
thirty-five milliamperes, isolate each circuit using the
fuse and circuit breaker remove-and-replace process
in Step 5. The multi-meter reading will drop to
within the acceptable limit when the source of the
excessive current draw is disconnected. Repair this
circuit as required; whether a wiring short, incorrect
switch adjustment, or a component failure is at fault.
STANDARD PROCEDURE - CHECKING BATTERY
ELECTROLYTE LEVEL
The following procedure can be used to check the
battery electrolyte level.
(1) Remove the battery cell caps (Fig. 10).
(2) Look through the battery cap holes to deter-
mine the level of the electrolyte in the battery (Fig.
11). The electrolyte should be approximately 1 centi-
meter above the battery plates or until the hook
inside the battery cap holes is covered.
(3) Add only distilled water until the electrolyte
level is approx. one centimeter above the plates.
Fig. 10 Battery Caps - Export Battery
1 - BATTERY CAP
2 - BATTERY
Fig. 11 Hook Inside Battery Cap Holes - Export
Battery
1 - BATTERY SURFACE COVER
2 - HOOK
8F - 14 BATTERY SYSTEMWJ
BATTERY (Continued)

The battery cables (Fig. 17) or (Fig. 18) are large
gauge, stranded copper wires sheathed within a
heavy plastic or synthetic rubber insulating jacket.
The wire used in the battery cables combines excel-
lent flexibility and reliability with high electrical cur-
rent carrying capacity. Refer toWiring Diagrams
for battery cable wire gauge information.
A clamping type female battery terminal made of
soft lead is die cast onto one end of the battery cable
wire. A square headed pinch-bolt and hex nut are
installed at the open end of the female battery termi-
nal clamp. Large eyelet type terminals are crimped
onto the opposite end of the battery cable wire and
then solder-dipped. The battery positive cable wires
have a red insulating jacket to provide visual identi-
fication and feature a larger female battery terminal
clamp to allow connection to the larger battery posi-
tive terminal post. The battery negative cable wires
have a black insulating jacket and a smaller female
battery terminal clamp.
The battery cables cannot be repaired and, if dam-
aged or faulty they must be replaced. Both the bat-
tery positive and negative cables are available for
service replacement only as a unit with the battery
wire harness, which may include portions of the wir-
ing circuits for the generator and other components
on some models. Refer toWiring Diagramsfor more
information on the various wiring circuits included in
the battery wire harness for the vehicle being ser-
viced.
OPERATION
The battery cables connect the battery terminal
posts to the vehicle electrical system. These cables
also provide a path back to the battery for electrical
current generated by the charging system for restor-
ing the voltage potential of the battery. The female
battery terminal clamps on the ends of the battery
cable wires provide a strong and reliable connection
of the battery cable to the battery terminal posts.
The terminal pinch bolts allow the female terminal
clamps to be tightened around the male terminal
posts on the top of the battery. The eyelet terminals
secured to the opposite ends of the battery cable
wires from the female battery terminal clamps pro-
vide secure and reliable connection of the battery
cables to the vehicle electrical system.
The battery positive cable terminal clamp is die
cast onto the ends of two wires. One wire has an eye-
let terminal that connects the battery positive cable
to the B(+) terminal stud of the Power Distribution
Center (PDC), and the other wire has an eyelet ter-
minal that connects the battery positive cable to the
B(+) terminal stud of the engine starter motor sole-
noid. The battery negative cable terminal clamp is
also die cast onto the ends of two wires. One wirehas an eyelet terminal that connects the battery neg-
ative cable to the vehicle powertrain through a stud
on the right side of the engine cylinder block. The
other wire has an eyelet terminal that connects the
battery negative cable to the vehicle body through a
ground screw on the right front fender inner shield,
near the battery.
DIAGNOSIS AND TESTING - BATTERY CABLES
A voltage drop test will determine if there is exces-
sive resistance in the battery cable terminal connec-
tions or the battery cable. If excessive resistance is
found in the battery cable connections, the connec-
tion point should be disassembled, cleaned of all cor-
rosion or foreign material, then reassembled.
Following reassembly, check the voltage drop for the
battery cable connection and the battery cable again
to confirm repair.
When performing the voltage drop test, it is impor-
tant to remember that the voltage drop is giving an
indication of the resistance between the two points at
which the voltmeter probes are attached.EXAM-
PLE:When testing the resistance of the battery pos-
itive cable, touch the voltmeter leads to the battery
positive cable terminal clamp and to the battery pos-
itive cable eyelet terminal at the starter solenoid
B(+) terminal stud. If you probe the battery positive
terminal post and the battery positive cable eyelet
terminal at the starter solenoid B(+) terminal stud,
you are reading the combined voltage drop in the
battery positive cable terminal clamp-to-terminal
post connection and the battery positive cable.
VOLTAGE DROP TEST
The following operation will require a voltmeter
accurate to 1/10 (0.10) volt. Before performing this
test, be certain that the following procedures are
accomplished:
²The battery is fully-charged and load tested.
Refer to Standard Procedures for the proper battery
charging and load test procedures.
²Fully engage the parking brake.
²If the vehicle is equipped with an automatic
transmission, place the gearshift selector lever in the
Park position. If the vehicle is equipped with a man-
ual transmission, place the gearshift selector lever in
the Neutral position and block the clutch pedal in the
fully depressed position.
²Verify that all lamps and accessories are turned
off.
²To prevent the engine from starting, remove the
Automatic Shut Down (ASD) relay. The ASD relay is
located in the Power Distribution Center (PDC), in
the engine compartment. See the fuse and relay lay-
out label affixed to the underside of the PDC cover
for ASD relay identification and location.
8F - 18 BATTERY SYSTEMWJ
BATTERY CABLE (Continued)

(1) Connect the positive lead of the voltmeter to
the battery negative terminal post. Connect the neg-
ative lead of the voltmeter to the battery negative
cable terminal clamp (Fig. 19). Rotate and hold the
ignition switch in the Start position. Observe the
voltmeter. If voltage is detected, correct the poor con-
nection between the battery negative cable terminal
clamp and the battery negative terminal post.
(2) Connect the positive lead of the voltmeter to
the battery positive terminal post. Connect the nega-
tive lead of the voltmeter to the battery positive cable
terminal clamp (Fig. 20). Rotate and hold the ignition
switch in the Start position. Observe the voltmeter. If
voltage is detected, correct the poor connection
between the battery positive cable terminal clamp
and the battery positive terminal post.
(3) Connect the voltmeter to measure between the
battery positive cable terminal clamp and the starter
solenoid B(+) terminal stud (Fig. 21). Rotate and hold
the ignition switch in the Start position. Observe the
voltmeter. If the reading is above 0.2 volt, clean and
tighten the battery positive cable eyelet terminal con-
nection at the starter solenoid B(+) terminal stud.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery positive cable.
(4) Connect the voltmeter to measure between the
battery negative cable terminal clamp and a good
clean ground on the engine block (Fig. 22). Rotate
and hold the ignition switch in the Start position.
Observe the voltmeter. If the reading is above 0.2
volt, clean and tighten the battery negative cable
eyelet terminal connection to the engine block.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery negative cable.
REMOVAL
Both the battery negative cable and the battery
positive cable are serviced in the battery wire har-
ness. If either battery cable is damaged or faulty, the
battery wire harness unit must be replaced.
(1) Turn the ignition switch to the Off position. Be
certain that all electrical accessories are turned off.
(2) Loosen the battery negative cable terminal
clamp pinch-bolt hex nut.
(3) Disconnect the battery negative cable terminal
clamp from the battery negative terminal post. If
necessary, use a battery terminal puller to remove
the terminal clamp from the battery post.
Fig. 19 TEST BATTERY NEGATIVE CONNECTION
RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
Fig. 20 TEST BATTERY POSITIVE CONNECTION
RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
Fig. 21 TEST BATTERY POSITIVE CABLE
RESISTANCE - TYPICAL
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
WJBATTERY SYSTEM 8F - 19
BATTERY CABLE (Continued)

(4) Loosen the battery positive cable terminal
clamp pinch-bolt hex nut.
(5) Disconnect the battery positive cable terminal
clamp from the battery positive terminal post. If nec-
essary, use a battery terminal puller to remove the
terminal clamp from the battery post.
(6) Unlatch and open the cover on the Power Dis-
tribution Center (PDC).
(7) Remove the two nuts that secure the battery
positive cable and generator output cable eyelet ter-
minal to the B(+) terminal studs in the PDC.
(8) Remove the battery positive cable and genera-
tor output cable eyelet terminal from the B(+) termi-
nal studs in the PDC.
(9) Disconnect the battery wire harness connector
from the right headlamp and dash wire harness con-
nector located near the front of the battery.
(10) Remove the screw that secures the battery
negative cable eyelet terminal to the inner fender
shield near the front of the battery.
(11) On models with the 4.7L engine, remove the
nut that secures the battery harness clip to the stud
on the right side of the intake manifold and remove
the clip from the stud.
(12) Unlatch and remove the cover from the gener-
ator output terminal stud housing on the back of the
generator.
(13) Remove the nut that secures the generator
output cable eyelet terminal to the generator output
terminal stud.
(14) Remove the generator output cable eyelet ter-
minal from the generator output terminal stud.
(15) Disconnect the battery wire harness connector
from the generator field terminal connector recepta-
cle on the back of the generator.(16) Remove the screw that secures the battery
negative cable ground eyelet terminal to the right
side of the engine block.
(17) Remove the nut that secures the battery pos-
itive cable eyelet terminal to the B(+) terminal stud
on the starter solenoid.
(18) Remove the battery positive cable eyelet ter-
minal from the B(+) terminal stud on the starter
solenoid.
(19) Disconnect the battery wire harness connector
from the connector receptacle on the starter solenoid.
(20) Remove the battery wire harness from the
engine compartment.
INSTALLATION
Both the battery negative cable and the battery
positive cable are serviced in the battery wire har-
ness. If either battery cable is damaged or faulty, the
battery wire harness unit must be replaced.
(1) Clean and inspect the battery cable terminal
clamps and the battery terminal posts.
(2) Position the battery wire harness into the
engine compartment (Fig. 23) or (Fig. 24).
(3) Reconnect the battery wire harness connector
to the connector receptacle on the starter solenoid.
(4) Install the battery positive cable eyelet termi-
nal onto the B(+) terminal stud on the starter sole-
noid.Fig. 22 TEST GROUND CIRCUIT RESISTANCE -
TYPICAL
1 - VOLTMETER
2 - BATTERY
3 - ENGINE GROUND
Fig. 23 Battery Cables - 4.0L Engine
1 - BATTERY POSITIVE CABLE
2 - BATTERY NEGATIVE CABLE
3 - CLIPS
8F - 20 BATTERY SYSTEMWJ
BATTERY CABLE (Continued)

(5) Install and tighten the nut that secures the
battery positive cable eyelet terminal to the B(+) ter-
minal stud on the starter solenoid. Tighten the nut to
11.3 N´m (100 in. lbs.).
(6) Install and tighten the screw that secures the
battery negative cable ground eyelet terminal to the
right side of the engine block. Tighten the screw to
10.2 N´m (90 in. lbs.) for 4.0L engines, or 13.0 N´m
(115 in. lbs.) for 4.7L engines.
(7) Reconnect the battery wire harness connector
to the generator field terminal connector receptacle
on the back of the generator.
(8) Install the generator output cable eyelet termi-
nal onto the generator output terminal stud.
(9) Install and tighten the nut that secures the
generator output cable eyelet terminal to the genera-
tor output terminal stud. Tighten the nut to 10.7
N´m (95 in. lbs.).
(10) Position the cover for the generator output
terminal stud housing onto the back of the generator
and snap it into place.
(11) On models with the 4.7L engine, install the
battery harness clip onto the stud on the right side of
the intake manifold, then install and tighten the nut
that secures the clip to the stud. Tighten the nut to
11.3 N´m (100 in. lbs.).
(12) Install and tighten the screw that secures the
battery negative cable eyelet terminal to the inner
fender shield near the front of the battery. Tighten
the screw to 28.2 N´m (250 in. lbs.).(13) Reconnect the battery wire harness connector
to the right headlamp and dash wire harness connec-
tor located near the front of the battery.
(14) Install the battery positive cable and genera-
tor output cable eyelet terminal onto the PDC B(+)
terminal studs.
(15) Install and tighten the two nuts that secure
the battery positive cable and generator output cable
eyelet terminal to the PDC B(+) terminal studs.
Tighten the nuts to 11.3 N´m (100 in. lbs.).
(16) Close and latch the PDC cover.
(17) Reconnect the battery positive cable terminal
clamp to the battery positive terminal post. Tighten
the terminal clamp pinch-bolt hex nut to 6.8 N´m (60
in. lbs.).
(18) Reconnect the battery negative cable terminal
clamp to the battery negative terminal post. Tighten
the terminal clamp pinch-bolt hex nut to 6.8 N´m (60
in. lbs.).
(19) Apply a thin coating of petroleum jelly or
chassis grease to the exposed surfaces of the battery
cable terminal clamps and the battery terminal
posts.BATTERY TRAY
DESCRIPTION
The battery is mounted in a molded plastic battery
tray and support unit (Fig. 25) located in the right
front corner of the engine compartment. The battery
tray and support unit is secured at the rear with a
nut to a stud on the front wheelhouse inner panel, at
the outboard side with a screw to the side cowl rein-
forcement panel, and at the front with a screw
through a U-nut on a bracket of the radiator support.
The battery tray and support unit also includes
three upright stanchions that are molded into the
outboard side of the unit. These stanchions support
the Power Distribution Center (PDC). Refer to
Power Distribution Centerin the Power Distribu-
tion section of this service manual for more informa-
tion on the PDC.
A hole in the bottom of the battery tray is fitted
with a battery temperature sensor. Refer toBattery
Temperature Sensorin the Charging section of
this service manual for more information on the bat-
tery temperature sensor. Refer toBattery Hold
Downin this section of the service manual for more
information on the battery hold down hardware.
Fig. 24 Battery Cables - 4.7L Engine
1 - BATTERY POSITIVE CABLE
2 - BATTERY NEGATIVE CABLE
3 - CLIPS
WJBATTERY SYSTEM 8F - 21
BATTERY CABLE (Continued)

INSTALLATION
(1) Clean and inspect the battery tray and support
unit. Refer to the procedures in this section of the
service manual.
(2) Install the battery temperature sensor onto the
battery tray. Refer toBattery Temperature Sensor
in the Charging section of this service manual for
battery temperature sensor installation procedure.
(3) Position the battery tray and support unit into
the right front corner of the engine compartment. Be
certain that no hoses or wire harnesses are trapped
or pinched by the installation of the tray.
(4) Install and tighten the one nut that secures the
rear of the battery tray and support unit to the stud
on the right fender front wheelhouse inner panel.
Tighten the nut to 7.3 N´m (65 in. lbs.).(5) Install and tighten the one screw that secures
the outboard side of the battery tray and support
unit to the right fender side cowl reinforcement.
Tighten the screw to 8.1 N´m (72 in. lbs.).
(6) Install and tighten the one screw that secures
the front of the battery tray and support unit to the
bracket on the right side of the radiator support.
Tighten the screw to 8.1 N´m (72 in. lbs.).
(7) Install the Power Distribution Center (PDC)
onto the stanchions on the outboard side of the bat-
tery tray and support unit. Refer toPower Distri-
bution Centerin the Power Distribution section of
this service manual for PDC installation procedure.
(8) Install the battery onto the battery tray (Refer
to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY -
INSTALLATION).
WJBATTERY SYSTEM 8F - 23
BATTERY TRAY (Continued)