Removal And Installation - Dodge ram truck 3500 1996 Service Manual

B R
CHARGING SYSTEM au - i
C H A R G I N G S Y S T E M
C O N T E N T S
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GENERAL INFORMATION
OVERVIEW 1
DESCRIPTION AND OPERATION
BATTERY TEMPERATURE SENSOR 2
CHARGING SYSTEM OPERATION 1
GENERATOR 2
VOLTAGE REGULATOR 2
DIAGNOSIS AND TESTING
BATTERY TEMPERATURE SENSOR 6
CHARGING SYSTEM RESISTANCE T E S T S 3
G E N E R A L I N F O R M A T I O N
OVERVIEW
The. battery, starting, and charging systems oper­
ate with one another, and must be tested as a com­
plete system. In order for the vehicle to start and
charge properly, all of the components Involved In
these systems must perform within specifications.
Group 8A covers the battery, Group 8B covers the
starting system, and Group 8C covers the charging
system. Refer to Group 8W - Wiring Diagrams for
complete circuit descriptions and diagrams. We have
separated these systems to make it easier to locate
the information you are seeking within this Service
Manual. However, when attempting to diagnose any
of these systems, i t Is important that you keep their
interdependency in mind.
The diagnostic procedures used In these groups
include the most basic conventional diagnostic meth­
ods to the more sophisticated On-Board Diagnostics
(OBD) built into the Powertrain Control Module
(PCM). Use of a induction milliampere ammeter, volt/
ohmmeter, battery charger, carbon pile rheostat (load
tester), and 12-volt test lamp may be required.
All OBD-sensed systems are monitored by the
PCM. Each monitored circuit is assigned a Diagnos­
tic Trouble Code (DTC). The PCM will store a DTC in
electronic memory for any failure i t detects. See the
On-Board Diagnostics Test i n Group 8C - Charging
System for more information.
page
CHARGING SYSTEM 2
CURRENT OUTPUT TEST . . . . . . . . . . . . . . . . . . 3
ON-BOARD DIAGNOSTIC SYSTEM TEST . . . . . . 6
REMOVAL AND INSTALLATION
BATTERY TEMPERATURE SENSOR . . . . . . . . . . 8
GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SPECIFICATIONS
GENERATOR RATINGS . . . . . . . . . . . . . . . . . . . . 9
TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . . 9
DESCRIPTION AND OPERATION
CHARGING SYSTEM OPERATION
The charging system consists of:
• Generator
• Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
• Ignition switch (refer to Group 8D, Ignition Sys­
tem for information)
• Battery (refer to Group 8A, Battery for informa­
tion)
• Battery temperature sensor
• Voltmeter (refer to Group 8E, Instrument Panel
and Gauges for information)
• Wiring harness and connections (refer to Group
8W, Wiring for Information)
The charging system is turned on and off with the
ignition switch. When the ignition switch is turned to
the ON position, battery voltage Is applied to the
generator rotor through one of the two field termi­
nals to produce a magnetic field. The generator is
driven by the engine through a serpentine belt and
pulley arrangement.
The amount of DC current produced by the gener­
ator is controlled by the EVR (field control) circuitry,
contained within the PCM. This circuitry is con­
nected in series with the second rotor field terminal
and ground.
A battery temperature sensor located In the bat­
tery tray housing, is used to sense battery tempera­
ture. This temperature data, along with data from
monitored line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling the
ground path to control the strength of the rotor mag­
netic field. The PCM then compensates and regulates
generator current output accordingly.