Jeep 1997 Grand Cherokee Service Manual page 1207

ZG
DESCRIPTION AND OPERATION
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
Power Distribution Center (PDC).
Circuit A1 from fuse 8 in the PDC supplies battery
voltage to the contact side of the engine starter
motor relay. When the coil side of the engine starter
motor relay energizes, the contacts close and connect
circuit A1 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
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.
8W - 21 STARTING SYSTEM
8W-21 STARTING SYSTEM
STARTING SYSTEM (DIESEL)
Power for the coil side of the engine starter motor
relay is supplied on circuit T141. This circuit is HOT
when the operator has moved the ignition key to the
START position and the clutch pedal position switch
is CLOSED.
Ground for the coil side of the relay is supplied on
circuit Z4.
When the coil side of the relay energizes the con-
tacts in the relay CLOSE connecting circuits A1 and
T40. The A1 circuit is protected by a 40 amp fuse
located in the Power Distribution Center (PDC). Cir-
cuit T40 connects from the relay to the solenoid in
the engine starter motor.
Power for the motor in the starter is supplied on
circuit A0. This is a direct feed from the battery.
Ground for the engine starter motor is supplied
through a case ground.
HELPFUL INFORMATION (DIESEL)
• Check the 40 amp fuse located in the PDC
• Check the clutch pedal position switch for proper
operation
• Check the case ground of the engine starter
motor
8W - 21 - 5