1995 JEEP YJ battery

the following procedures to reduce the possibility of
electrostatic charge build up on the body and inad-
vertent discharge into the component. If it is not
known whether the part is ESD sensitive, assume
that it is.
(1) Always touch a known good ground before han-
dling the part. This should be repeated while han-
dling the part and more frequently after sliding
across a seat, sitting down from a standing position,
or walking a distance.
(2) Avoid touching electrical terminals of the part,
unless instructed to do so by a written diagnostic
procedure.
(3) When using a voltmeter, be sure to connect the
ground lead first.
(4) Do not remove the part from its protective pack-
ing until it is time to install the part.
(5) Before removing the part from its package,
ground the package to a known good ground on the
vehicle.
TROUBLESHOOTING TOOLS
When diagnosing a problem in an electrical circuit
there are several common tools necessary. These tools
are listed and explained below.
²Jumper Wire - This is a test wire used to connect
two points of a circuit. It can be used to bypass an
open in a circuit.
WARNING: NEVER USE A JUMPER WIRE ACROSS A
LOAD, SUCH AS A MOTOR, CONNECTED BETWEEN
A BATTERY FEED AND GROUND.
²Voltmeter - Used to check for voltage on a circuit.
Always connect the black lead to a known good
ground and the red lead to the positive side of the
circuit.
CAUTION: Most of the electrical components used
in today's vehicle are solid state. When checking
voltages in these circuits use a meter with a 10-
megohm or greater impedance.
²Ohmmeter - Used to check the resistance between
two points of a circuit. Low or no resistance in a
circuit means good continuity.CAUTION: - Most of the electrical components used
in today's vehicle are Solid State. When checking
resistance in these circuits use a meter with a 10-
megohm or greater impedance. In addition, make
sure the power is disconnected from the circuit.
Circuits that are powered up by the vehicle electrical
system can cause damage to the equipment and
provide false readings.
²Probing Tools - These tools are used for probing
terminals in connectors (Fig. 7). Select the proper size
tool from Special Tool Package 6807, and insert it into
the terminal being tested. Use the other end of the
tool to insert the meter probe.
INTERMITTENT AND POOR CONNECTIONS
Most intermittent electrical problems are caused by
faulty electrical connections or wiring. It is also pos-
sible for a sticking component or relay to cause a
problem. Before condemning a component or wiring
assembly check the following items.
²Connectors are fully seated
²Spread terminals, or terminal push out
²Terminals in the wiring assembly are fully seated
into the connector/component and locked in position
²Dirt or corrosion on the terminals. Any amount of
corrosion or dirt could cause an intermittent problem
²Damaged connector/component casing exposing the
item to dirt and moisture
²Wire insulation that has rubbed through causing a
short to ground
²Wiring broke inside of the insulation
TROUBLESHOOTING TESTS
Before beginning any tests on a vehicle's electrical
system, use the Wiring Diagrams and study the cir-
cuit. Also refer to the Troubleshooting Wiring Prob-
lems section in this section.
TESTING FOR VOLTAGE
(1) Connect the ground lead of a voltmeter to a
known good ground (Fig. 8).
Fig. 6 Electrostatic Discharge Symbol
Fig. 7 Probing Tool
8W - 4 WIRING DIAGRAMSÐGENERAL INFORMATIONJ

(2) Connect the other lead of the voltmeter to the
selected test point. The vehicle ignition may need to
be turned ON to check voltage. Refer to the appropri-
ate test procedure.
TESTING FOR CONTINUITY
(1) Remove the fuse for the circuit being checked or,
disconnect the battery.
(2) Connect one lead of the ohmmeter to one side of
the circuit being tested (Fig. 9).
(3) Connect the other lead to the other end of the
circuit being tested. Low or no resistance means good
continuity.
TESTING FOR A SHORT TO GROUND
(1) Remove the fuse and disconnect all items in-
volved with the fuse.
(2) Connect a test light or a voltmeter across the
terminals of the fuse.
(3) Starting at the fuse block, wiggle the wiring
harness about six to eight inches apart and watch the
voltmeter/test lamp.
(4) If the voltmeter registers voltage or the test
lamp glows, there is a short to ground in that general
area of the wiring harness.
TESTING FOR A SHORT TO GROUND ON
FUSES POWERING SEVERAL LOADS
(1) Refer to the wiring diagrams and disconnect or
isolate all items on the fused circuit.
(2) Replace the blown fuse.
(3) Supply power to the fuse by turning ON the
ignition switch or re-connecting the battery.(4) Start connecting the items in the fuse circuit
one at a time. When the fuse blows the circuit with
the short to ground has been isolated.
TESTING FOR A VOLTAGE DROP
(1) Connect the positive lead of the voltmeter to the
side of the circuit closest to the battery (Fig. 10).
(2) Connect the other lead of the voltmeter to the
other side of the switch or component.
(3) Operate the item.
(4) The voltmeter will show the difference in volt-
age between the two points.
TROUBLESHOOTING WIRING PROBLEMS
When troubleshooting wiring problems there are six
steps which can aid in the procedure. The steps are
listed and explained below. Always check for non-
factory items added to the vehicle before doing any
diagnosis. If the vehicle is equipped with these items,
disconnect them to verify these add-on items are not
the cause of the problem.
(1) Verify the problem.
(2) Verify any related symptoms. Do this by per-
forming operational checks on components that are in
the same circuit. Refer to the wiring diagrams.
(3) Analyze the symptoms. Use the wiring dia-
grams to determine what the circuit is doing, where
the problem most likely is occurring and where the
diagnosis will continue.
(4) Isolate the problem area.
(5) Repair the problem.
(6) Verify proper operation. For this step, check for
proper operation of all items on the repaired circuit.
Refer to the wiring diagrams.
Fig. 8 Testing for Voltage
Fig. 9 Testing for Continuity
JWIRING DIAGRAMSÐGENERAL INFORMATION 8W - 5

WIRING REPAIR
When replacing or repairing a wire, it is important
that the correct gauge be used as shown in the wiring
diagrams. The wires must also be held securely in
place to prevent damage to the insulation.
(1) Disconnect battery negative cable.
(2) Remove 1 inch of insulation from each end of
the wire.
(3) Place a piece of heat shrink tubing over one side
of the wire. Make sure the tubing will be long enough
to cover and seal the entire repair area.
(4) Spread the strands of the wire apart on each
part of the exposed wires (Fig. 11 example 1).
(5) Push the two ends of wire together until the
strands of wire are close to the insulation (Fig. 11
example 2).
(6) Twist the wires together (Fig. 11 example 3).
(7) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(8) Center the heat shrink tubing over the joint,
and heat using a heat gun. Heat the joint until the
tubing is tightly sealed and sealant comes out of both
ends of the tubing.
(9) Secure the wire to the existing ones to prevent
chafing or damage to the insulation.
(10) Connect battery and test all affected systems.
TERMINAL/CONNECTOR REPAIRÐMOLEX
CONNECTORS
(1) Disconnect battery.
(2) Disconnect the connector from its mating half/
component.
(3) Insert the terminal releasing special tool 6742
into the terminal end of the connector (Fig. 12).(4) Using special tool 6742, release the locking fin-
gers on the terminal (Fig. 13).
(5) Pull on the wire to remove it from the connec-
tor.
(6) Repair or replace the connector or terminal as
necessary.
CONNECTOR REPLACEMENT
(1) Disconnect battery.
(2) Disconnect the connector that is to be repaired
from its mating half/component.
(3) Remove connector locking wedge, if required
(Fig. 14).
(4) Position the connector locking finger away from
the terminal using the proper pick from special tool
kit 6680. Pull on the wire to remove the terminal
from the connector (Fig. 15, and Fig. 16).
Fig. 10 Testing for Voltage DropFig. 11 Wire Repair
Fig. 12 Molex Connector Repair
8W - 6 WIRING DIAGRAMSÐGENERAL INFORMATIONJ

(5) Reset the terminal locking tang, if it has one.
(6) Insert the removed wire in the same cavity on
the repair connector.
(7) Repeat steps four through six for each wire in
the connector, being sure that all wires are inserted
into the proper cavities. For additional connector pin-
out identification, refer to the wiring diagrams.
(8) Insert the connector locking wedge into the re-
paired connector, if required.
(9) Connect connector to its mating half/component.
(10) Connect battery and test all affected systems.
CONNECTOR AND TERMINAL REPLACEMENT
(1) Disconnect battery.
(2) Disconnect the connector (that is to be repaired)
from its mating half/component.
(3) Cut off the existing wire connector directly be-
hind the insulator. Remove six inches of tape from the
harness.
(4) Stagger cut all wires on the harness side at 1/2
inch intervals (Fig. 17).(5) Remove 1 inch of insulation from each wire on
the harness side.
(6) Stagger cut the matching wires on the repair
connector assembly in the opposite order as was done
on the harness side of the repair. Allow extra length
for soldered connections. Check that the overall
length is the same as the original (Fig. 17).
(7) Remove 1 inch of insulation from each wire.
(8) Place a piece of heat shrink tubing over one side
of the wire. Be sure the tubing will be long enough to
cover and seal the entire repair area.
(9) Spread the strands of the wire apart on each
part of the exposed wires (Fig. 11 example 1).
(10) Push the two ends of wire together until the
strands of wire are close to the insulation (Fig. 11
example 2).
(11) Twist the wires together (Fig. 11 example 3).
(12) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(13) Center the heat shrink tubing over the joint
and heat using a heat gun. Heat the joint until the
tubing is tightly sealed and sealant comes out of both
ends of the tubing.
Fig. 13 Using Special Tool 6742
Fig. 14 Connector Locking Wedge Tab (Typical)
Fig. 15 Terminal Removal
Fig. 16 Terminal Removal Using Special Tool
JWIRING DIAGRAMSÐGENERAL INFORMATION 8W - 7

(14) Repeat steps 8 through 13 for each wire.
(15) Re-tape the wire harness starting 1-1/2 inches
behind the connector and 2 inches past the repair.
(16) Re-connect the repaired connector.
(17) Connect the battery, and test all affected sys-
tems.
TERMINAL REPLACEMENT
(1) Disconnect battery.
(2) Disconnect the connector being repaired from
its mating half.
(3) Remove connector locking wedge, if required
(Fig. 14).
(4) Position the connector locking finger away from
the terminal using the proper pick from special tool
kit 6680. Pull on the wire to remove the terminal
from the connector (Figs. 15 and 16).
(5) Cut the wire 6 inches from the back of the
connector.
(6) Remove 1 inch of insulation from the wire on
the harness side.
(7) Select a wire from the terminal repair assembly
that best matches the color wire being repaired.
(8) Cut the repair wire to the proper length and
remove 1 inch of insulation.
(9) Place a piece of heat shrink tubing over one side
of the wire. Make sure the tubing will be long enough
to cover and seal the entire repair area.
(10) Spread the strands of the wire apart on each
part of the exposed wires (Fig. 11 example 1).
(11) Push the two ends of wire together until the
strands of wire are close to the insulation (Fig. 11
example 2).
(12) Twist the wires together (Fig. 11 example 3).(13) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(14) Center the heat shrink tubing over the joint
and heat using a heat gun. Heat the joint until the
tubing is tightly sealed and sealant comes out of both
ends of the tubing.
(15) Insert the repaired wire into the connector.
(16) Install the connector locking wedge, if re-
quired, and reconnect the connector to its mating
half/component.
(17) Re-tape the wire harness starting 1-1/2 inches
behind the connector and 2 inches past the repair.
(18) Connect the battery, and test all affected sys-
tems.
DIODE REPLACEMENT
(1) Disconnect the battery.
(2) Locate the diode in the harness, and remove the
protective covering.
(3) Remove the diode from the harness, pay atten-
tion to the current flow direction (Fig. 18).
(4) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
(5) Install the new diode in the harness, making
sure current flow is correct. If necessary, refer to the
appropriate wiring diagram for current flow.
(6) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(7) Tape the diode to the harness using electrical
tape. Make sure the diode is completely sealed from
the elements.
(8) Re-connect the battery, and test affected sys-
tems.Fig. 17 Stagger Cutting Wires (Typical)
Fig. 18 Diode Identification
8W - 8 WIRING DIAGRAMSÐGENERAL INFORMATIONJ

CHARGING SYSTEM
CHARGING SYSTEM
The charging system is an integral part of the bat-
tery and starting systems. Because all these systems
work in conjunction, diagnose and test them together.
Circuit A11 connects to the generator output termi-
nal and splices to fuse 1 and fuse 8 in the Power Dis-
tribution Center (PDC). Circuit A0 connects the
battery to the PDC.
Circuit Z0 provides ground for the generator. Cir-
cuit Z0 attaches to the right rear of the engine.
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the PDC to circuit A21. Circuit A21 splices to supply
current to the coil side of the automatic shut down
(ASD) relay. The powertrain control module (PCM)
provides ground for the relay on circuit K51. Circuit
K51 connects to cavity 51 of the PCM.
When the PCM grounds the ASD relay, contacts in-
side the relay close and connect circuit A18 from fuse
14 in the PDC to circuit A142. Circuit A142 splices to
the generator field terminal.
The PCM has an internal voltage regulator that
controls generator output. The PCM controls the gen-
erator field on circuit K20. Circuit K20 connects to
PCM cavity 20.
When the engine operates and there is current in
the generator field, the generator produces a B+ volt-
age. The generator supplies B+ voltage to the battery
through the A11 and A0 circuits.
HELPFUL INFORMATION
²If the vehicle is equipped with a 2.5L engine, cir-
cuit Z0 also connects to the battery.
²Circuit A14 from fuse 2 in the PDC supplies volt-
age to the fuse block for fuse 14.
²The ignition switch also connects circuit A1 with
circuits A41, A38, and A48.
²Circuit A21 also splices to power fuse 17 in the
fuse block.
²Circuit A21 also powers the coil side of the fuel
pump relay.
²The ASD relay supplies battery voltage for the fuel
injectors, ignition coil, and the heated oxygen sensor.
The fuel pump relay powers the fuel pump module.
²Circuit K51 also provides ground for the coil side
of the fuel pump relay.
DIAGRAM INDEX
Component Page
Battery (2.5L)...........................8W-20-2
Battery (4.0L)...........................8W-20-3
PDC Fuse 1 (2.5L).......................8W-20-2
PDC Fuse 1 (4.0L).......................8W-20-3
PDC Fuse 9 (2.5L).......................8W-20-2
PDC Fuse 9 (4.0L).......................8W-20-3
Generator (2.5L).........................8W-20-2
Generator (4.0L).........................8W-20-3
Powertrain Control Module (2.5L)..............8W-20-2
Powertrain Control Module (4.0L)..............8W-20-3
J8W-20 CHARGING SYSTEMÐXJ VEHICLES 8W - 20 - 1

STARTING SYSTEM
INDEX
page page
Diagram Index............................ 1Starting System........................... 1
STARTING SYSTEM
AUTOMATIC TRANSMISSIONS
Circuit A0 from the battery is double crimped at
the positive battery post. One branch of circuit A0
(battery positive cable) connects to the engine starter
motor. The other A0 branch supplies voltage to the
bus bar in the power distribution center (PDC).
Fuse 7 in the PDC supplies battery voltage to the
contact side of the engine starter motor relay on cir-
cuit A4. When the coil side of the engine starter mo-
tor relay energizes, the contacts close and connect
circuit A4 to circuit T40. Circuit T40 supplies battery
voltage to the starter motor solenoid.
The ignition switch supplies battery voltage to the
coil side of the starter motor relay on circuit A41
when the key is moved to the START position and
the PARK/NEUTRAL position switch is closed.
Ground for the coil side of the starter motor relay is
supplied by the case grounded PARK/NEUTRAL po-
sition switch. Circuit T41 connects the coil side of the
relay to the PARK/NEUTRAL position switch.
When the starter motor relay energizes and the
contacts close, circuit T40 supplies battery voltage to
the starter motor solenoid. Circuit A0 from the bat-
tery supplies voltage to the starter motor when the
solenoid energizes.
MANUAL TRANSMISSIONS
Circuit A0 from the battery is double crimped at
the positive battery post. One branch of circuit A0
(battery positive cable) connects to the battery
starter motor. The other A0 branch supplies voltage
to the buss bar in the power distribution center
(PDC).
Fuse 7 in the PDC supplies battery voltage to the
contact side of the engine starter motor relay on cir-
cuit A4. When the coil side of the engine starter mo-
tor relay energizes, the contacts close and connect
circuit A4 to circuit T40. Circuit T40 supplies battery
voltage to the starter motor solenoid.The ignition switch supplies battery voltage to the
coil side of the starter motor relay on circuit A41
when the key is moved to the START position. Cir-
cuit Z12 provides ground for the coil side of the relay.
When the starter motor relay energizes and the
contacts close, circuit T40 supplies battery voltage to
the starter motor solenoid. Circuit A0 from the bat-
tery supplies voltage to the starter motor when the
solenoid energizes.
HELPFUL INFORMATION
²The Park/Neutral switch closes when the trans-
mission is in either the PARK or NEUTRAL posi-
tions.
²Circuit T41 also connects to cavity 30 of the pow-
ertrain control module (PCM). This input tells the
PCM the operator is starting the vehicle.
²Circuit A4 is double crimped at the contact side of
the starter motor relay. The A4 branch leaving the
relay powers fuse 13 in the PDC.
DIAGRAM INDEX
Component Page
Battery (2.5L)...........................8W-21-2
Battery (4.0L)...........................8W-21-3
Engine Starter Motor (2.5L)..................8W-21-2
Engine Starter Motor (4.0L)..................8W-21-3
Engine Starter Motor Relay (2.5L)..............8W-21-2
Engine Starter Motor Relay (4.0L)..............8W-21-3
Ignition Switch (2.5L)......................8W-21-2
Ignition Switch (4.0L)......................8W-21-3
PDC Fuse 6 (2.5L).......................8W-21-2
PDC Fuse 6 (4.0L).......................8W-21-3
PDC Fuse 7 (2.5L).......................8W-21-2
PDC Fuse 7 (4.0L).......................8W-21-3
Powertrain Control Module (2.5L)..............8W-21-2
Powertrain Control Module (4.0L)..............8W-21-3
Park/Neutral Position Switch (2.5L).............8W-21-2
Park/Neutral Position Switch (4.0L).............8W-21-3
J8W-21 STARTING SYSTEMÐXJ VEHICLES 8W - 21 - 1

FUEL/IGNITION
INDEX
page page
Automatic Shut Down (ASD) Relay............. 1
Battery Feed.............................. 1
Brake Switch Input......................... 5
Camshaft Position Sensor.................... 3
CCDBus ................................ 5
Crankshaft Position Sensor................... 3
Data Link Connector........................ 5
Diagram Index Ð2.5L Engine.................. 6
Diagram Index Ð4.0L Engine.................. 6
Engine Coolant Temperature Sensor............ 3
Extended Idle Switch....................... 5
Fuel Injectors............................. 1
Fuel Pump Module......................... 2
Fuel Pump Relay.......................... 2
Heated Oxygen Sensor...................... 3Idle Air Control (IAC) Motor................... 2
Ignition Coil.............................. 2
Ignition Switch............................ 1
Intake Air Temperature Sensor................ 4
Malfunction Indicator Lamp (MIL)............... 5
Manifold Absolute Pressure Sensor............. 4
Park/Neutral Position Switch.................. 4
Power (Device) Ground...................... 5
Power Steering Pressure Switch............... 5
Tachometer Signal......................... 5
Throttle Position Sensor..................... 4
Torque Converter Clutch (TCC) Solenoid and
Relay................................. 4
Upshift Lamp............................. 5
Vehicle Speed Sensor....................... 2
IGNITION SWITCH
Circuit A1 from fuse 11 in the power distribution
center (PDC), supplies battery voltage to the ignition
switch. Depending upon position, the ignition switch
powers circuits A21, A38, A41, or A48.
START POSITION
In the START position, the ignition switch connects
circuit A1 to circuit A41. Circuit A41 connects to the
coil side of the starter motor relay.
Additionally in the START position, the case
grounded ignition switch provides ground for the
brake lamp switch and the warning lamps in the
instrument cluster.
START OR RUN POSITION
In the START or RUN position, the ignition switch
connects circuit A1 to circuit A21. Circuit A21 splices
to power fuse 17 in the fuse block and the coil side of
the Automatic Shut Down (ASD) relay and the fuel
pump relay.
RUN (ONLY) POSITION
When the ignition switch is in the RUN position, it
connects circuit A1 to circuit A38. Circuit A22 splices
to power fuses 1 and 7 in the fuse block.
²Fuse 1 powers the rear wiper system on circuit
V15.
²Fuse 7 feeds the Anti-Lock Brake System (ABS) on
circuit 236.
ACCESSORY OR RUN POSITIONS
In the ACCESSORY or RUN positions, the ignition
switch connects circuit A1 to circuit A48. Circuit A48
connects to a bus bar in the fuse block that feeds
fuses 2, 5, and 8.
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 supplies battery voltage to the coil side of
the Automatic Shut Down (ASD) relay. The Power-
train Control Module (PCM) provides ground for the
relay on circuit K51. Circuit K51 connects to cavity 51
of the PCM.
When the PCM grounds the ASD relay, contacts
inside the relay close and connect circuit A18 from
fuse 14 in the PDC to circuit A142. Circuit A142
splices to the generator field terminal, fuel injectors,
and ignition coil. Circuit A142 also connects to cavity
57 of the PCM.
HELPFUL INFORMATION
²Along with supplying voltage to the coil side of the
ASD relay, circuit A21 also supplies voltage to the coil
side of the fuel pump relay.
BATTERY FEED
Circuit A14 from fuse 2 in the Power Distribution
Center (PDC) supplies battery voltage to cavity 3 of
the powertrain control module.
HELPFUL INFORMATION
Circuit A14 also supplies power to the contact sides
of the fuel pump relay and fuse F2 in the PDC. Fuse
F2 powers circuit A18 which supplies voltage to the
contact side of the automatic shut down relay.
FUEL INJECTORS
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
J8W-30 FUEL/IGNITIONÐXJ VEHICLES 8W - 30 - 1