JEEP YJ 1995 Service And Repair Manual

GROUND DISTRIBUTION
GENERAL INFORMATION
This section identifies the vehicle grounds, splices
connected to each ground, and the components con-
nected to each ground. Refer to the appropriate sec-
tion of the wiring diagrams for circuit descriptions of
specific systems. Refer to sub-section 8W-90 for illus-
trations of the physical location of each ground on
the vehicle.
DIAGRAM INDEX
Component Page
G101................................8W-15-2
G102................................8W-15-2
G103................................8W-15-2
G104................................8W-15-3
G105................................8W-15-3
G106................................8W-15-3
G107................................8W-15-3
G108................................8W-15-3
G201 (With ABS).......................8W-15-4, 6
G201 (Without ABS).....................8W-15-5, 6
G301.............................8W-15-4, 5, 6
S102................................8W-15-2
S103................................8W-15-2
S112................................8W-15-3
S117................................8W-15-3
S120................................8W-15-2
S203...............................8W-15-4, 6
S204...............................8W-15-4, 6
S222...............................8W-15-5, 6
S306.............................8W-15-4, 5, 6
S309.............................8W-15-4, 5, 6
J8W-15 GROUND DISTRIBUTIONÐXJ-RHD 8W - 15 - 1

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 9 in the Power Dis-
tribution Center (PDC). Circuit A0 connects the
battery to the PDC. Circuit Z0 provides ground for
the generator.
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
²Circuit A14 from fuse 2 in the PDC supplies volt-
age to PDC fuse 14.
²The ignition switch also connects circuit A1 with
circuits A41, A38, and A48.
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...............................8W-20-2
PDC Fuse 1............................8W-20-2
PDC Fuse 9............................8W-20-2
Generator..............................8W-20-2
Powertrain Control Module..................8W-20-2
J8W-20 CHARGING SYSTEMÐXJ-RHD 8W - 20 - 1

STARTING SYSTEM
STARTING SYSTEM
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.
Ground for the coil side of the starter motor relay is
supplied by the case grounded Park/Neutral position
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.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
Engine Starter Motor......................8W-21-2
Engine Starter Motor Relay..................8W-21-2
Ignition Switch..........................8W-21-2
PDC Fuse 6............................8W-21-2
PDC Fuse 7............................8W-21-2
PDC Fuse 13...........................8W-21-2
Powertrain Control Module..................8W-21-2
Park/Neutral Position Switch.................8W-21-2
Transmission Control Module.................8W-21-2
J8W-21 STARTING SYSTEMÐXJ-RHD 8W - 21 - 1