Dodge RAM TRUCK 1500 1995 Service Manual page 571

B R
8W-21 STARTING SYSTEM 8W - 21 - 1
STARTING SYSTEM
AUTOMATIC TRANSMISSION
The Power Distribution Center (PDC) supplies bat­
tery voltage to the engine starter motor solenoid on
circuit T40 when the coil side of the engine starter
motor relay energizes.
Circuit AO from the battery is double crimped at
the positive battery post. One branch of circuit AO
(battery positive cable) connects to the starter motor.
The other AO branch supplies voltage to a bus bar in
the PDC. Fuse 2 (40 amp) connects to the bus bar
and protects circuit A2. Circuit A2 connects to the
contact side of the engine starter motor relay.
The ignition switch supplies battery voltage to the
coil side of the engine 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
switch. Circuit T41 connects the coil side of the relay
to the PARK/NEUTRAL switch.
When the starter motor relay energizes and the
contacts close, circuit T40 supplies battery voltage to
the starter motor solenoid. Circuit AO from the bat­
tery supplies voltage to the starter motor when the
solenoid energizes.
HELPFUL INFORMATION ^ . .
• Check the 40 amp fuse located in cavity 2 of the
PDC
• The PARK/NEUTRAL switch CLOSES when the
transmission is in either the PARK or NEUTRAL po­
sitions
• Circuit T41 splices to cavity 30 of the Powertrain
Control Module (PCM) This input tells the PCM the
operator is starting the vehicle
• Circuit T41 is spliced to circuit Zl. Circuit Zl pro­
vides ground for the vehicle speed sensor, A/C com­
pressor clutch, 4x4 switch, vehicle speed control,
heated oxygen sensor, and PCM. The engine will
not start if the vehicle loses this ground.
• On diesel engines the T40 circuit is spliced and
supplies power for the fuel shut down solenoid
MANUAL TRANSMISSION
The Power Distribution Center (PDC) supplies bat­
tery voltage to the engine starter motor solenoid on
circuit T40 when the coil side of the engine starter
motor relay energizes.
Circuit AO from the battery is double crimped at
the positive battery post. One branch of circuit AO
(battery positive cable) connects to the battery
starter motor. The other AO branch supplies voltage
to a bus bar in the PDC. Fuse 2 (40 amp) connects to
the bus bar and protects circuit A2. Circuit A2 con­
nects to the contact side of the engine starter motor
relay.
The ignition switch supplies battery voltage to the
coil side of the engine starter motor relay on circuit
A41 when the key is moved to the START position
and the operator depresses the clutch pedal. When
the operator depresses the clutch pedal, the clutch
pedal position switch CLOSES. Ground for the coil
side of the engine starter motor relay is supplied on
circuit T41. This circuit is spliced with circuit Z12.
Circuit Z12 connects to ground.
When the starter motor relay energizes and the
contacts CLOSE, circuit T40 supplies battery voltage
to the starter motor solenoid. Circuit AO from the
battery supplies voltage to the starter motor when
the solenoid energizes.
HELPFUL INFORMATION
• Check the 40 amp fuse located in cavity 2 of the
PDC
• Circuit Zl also provides ground for the vehicle
speed sensor, A/C compressor clutch, 4x4 switch, ve­
hicle speed control, heated oxygen sensor, and PCM.
The engine will not start if the vehicle loses
this ground. The grounding point for the Zl ground
is the left side shield.
• On diesel engines the T40 circuit is spliced and
supplies power for the fuel shut down solenoid
DIAGRAM INDEX
Component Page
Clutch Pedal Position Switch 8W-21-2
Engine Starter Motor 8W-21-2
Engine Starter Motor Relay 8W-21-2
Fuse 2 (PDC) 8W-21-2
Fuse 3 (PDC) . . . . . . . . . . . .8W-21-2
Ignition Switch .8W-21-2
Park/Neutral Position Switch 8W-21-2