Dodge RAM TRUCK 1500 1995 Service Manual page 566

B R
8W-20 CHARGING SYSTEM 8W - 20 - 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 AO from the battery connects to a bus bar
in the Power Distribution Center (PDC). Circuit A l l
connects to the PDC bus bar and the output terminal
of the generator. A fuse in the PDC between AO and
All circuits protects the charging system. Circuit Zl
provides ground for the generator.
On the diesel engine applications an additional bat­
tery is used. Circuit AO connects between the battery
positive terminals of the batteries.
When the ignition switch is in either the START or
RUN positions, it connects battery voltage from cir­
cuit Al to the A21 circuit. Circuit A21 powers circuit
F18 through Fuse 9 in the fuse block. Circuit F18
connects to the coil side of the Automatic Shut Down
(ASD) relay. Circuit Al originates in the PDC and is
connected to battery voltage. A 40 amp fuse in cavity
3 of the PDC protects the Al circuit.
When the ASD relay energizes, it contacts connect
circuit A14 from the PDC to circuit A142. Circuit
A142 splices to connect to the generator connector
supplying battery voltage to the generator field.
The Powertrain Control Module (PCM) has an in­
ternal voltage regulator that controls generator out­
put. Circuit K20 connects to generator and PCM
cavity 20. The PCM controls the generator field on
the K20 circuit.
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 A l l and AO circuits.
• From the ASD relay, circuit A142 splices to supply
voltage to the fuel injectors, ignition coil, fuel pump
module, and the heated oxygen sensor on gasoline
engines.
DIAGRAM INDEX—GASOLINE ENGINES
Component Page
ASD
Relay
8W-20-3
Clutch Pedal Position Switch 8W-20-3
Engine Starter Motor .8W-20-3
Engine Starter Motor Relay 8W-20-3
Fuse 2 (PDC) .8W-20-2
Fuse 3 (PDC)
8W-20-2
Fuse 4 (PDC) 8W-20-2
Generator 8W-20-2
Ignition Switch 8W-20-3
Powertrain Control Module 8W-20-2
DIAGRAM INDEX—DIESEL ENGINES
Component Page
ASD Relay 8W-20-5
Clutch Pedal Position Switch .8W-20-5
Engine Starter Motor Relay 8W-20-5
Engine Starter Motor . 8W-20-5
Fuse 2 (PDC) 8W-20-4
Fuse 3 (PDC)
. . . . . . . .8W-20-4
Fuse 4 (PDC) 8W-20-4
Generator 8W-20-4
Ignition Switch 8W-20-5
Powertrain Control Module 8W-20-4
HELPFUL
I N F Q i i A T I O N
• Check the 120 amp fuse located in the PDC