Dodge Ram Truck 1500-2500-3500. Manual - part 320

Vehicles with a gasoline engine are equipped with a
single 12-volt battery. All of the components of the bat-
tery system are located within the engine compart-
ment. The battery system for this vehicle, covers the
following related components:

•

Battery (2) - The storage battery provides a reli-
able means of storing a renewable source of
electrical energy within the vehicle.

•

Positive Battery cable (1) - The positive battery
cable connects the battery positive terminal post
to the vehicle electrical system, starter and alter-
nator.

•

Negative Battery Cable (3) - The negative bat-
tery cable connects the battery negative terminal
post to the vehicle electrical system through
body, chassis and engine grounding points.

•

Battery Thermal Guard (5) - A thermal guard
wraps around the battery case to enclose the
sides of the battery. The thermal guard consists
of a heavy black plastic outer skin and two lighter plies of plastic that have been formed into a sheet with
hundreds of small air pockets entrapped between them.

•

Battery Holddown - The battery holddown hardware secures the battery in the battery tray in the engine com-
partment.

•

Battery Tray - The battery tray provides a secure mounting location in the vehicle for the battery and an
anchor point for the battery holddown hardware.

DIESEL ENGINE

Vehicles with a diesel engine utilize two 12-volt batter-
ies connected in parallel. All of the components of the
battery system are located within the engine compart-
ment. The battery system for this vehicle, covers the
following related components:

•

Left Battery (3) - The Left storage battery pro-
vides a reliable means of storing a renewable
source of electrical energy within the vehicle.

•

Right Battery (5) - The Right storage battery
provides a reliable means of storing a renewable
source of electrical energy within the vehicle as
well as the additional required electrical energy
due to high demands of the diesel system.

•

Positive Battery cables (2 & 6) - The positive
battery cables connect the battery positive termi-
nal posts to the vehicle electrical system, starter
and alternator as well as connecting the two bat-
teries together.

•

Negative Battery Cables (1 & 4) - The negative
battery cables connect the battery negative terminal posts to the vehicle electrical system through body, chas-
sis and engine grounding points.

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BATTERY SYSTEM

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•

Battery Thermal Guard - A thermal guard wraps around the battery case to enclose the sides of the battery.
The thermal guard consists of a heavy black plastic outer skin and two lighter plies of plastic that have been
formed into a sheet with hundreds of small air pockets entrapped between them.

•

Battery Holddown - The battery holddown hardware secures the battery in the battery tray in the engine com-
partment.

•

Battery Tray - The battery tray provides a secure mounting location in the vehicle for the battery and an
anchor point for the battery holddown hardware.

For battery system maintenance schedules, (Refer to LUBRICATION & MAINTENANCE/MAINTENANCE SCHED-
ULES - DESCRIPTION). For the proper battery jump starting procedure, (Refer to LUBRICATION & MAINTE-
NANCE/JUMP STARTING - STANDARD PROCEDURE). The battery must be fully-charged before any battery
system diagnosis or testing procedures can be performed.

OPERATION

The battery system is designed to provide a safe, efficient, reliable and mobile means of delivering and storing
electrical energy. This electrical energy is required to operate the engine starting system, as well as many of the
other vehicle accessory systems for limited durations while the engine and/or the charging system are not operating.
The battery system is also designed to provide a reserve of electrical energy to supplement the charging system for
short durations while the engine is running and the electrical current demands of the vehicle exceed the output of
the charging system. In addition to delivering, and storing electrical energy for the vehicle, the battery system serves
as a capacitor and voltage stabilizer for the vehicle electrical system. It absorbs most abnormal or transient voltages
caused by the switching of any of the electrical components or circuits in the vehicle.

DIAGNOSIS AND TESTING

BATTERY SYSTEM

The battery, starting, and charging systems in the vehicle operate with one another and must be tested as a com-
plete system. In order for the engine to start and the battery to maintain its charge properly, all of the components
that are used in these systems must perform within specifications. It is important that the battery, starting, and
charging systems be thoroughly tested and inspected any time a battery needs to be charged or replaced. The
cause of abnormal battery discharge, overcharging or early battery failure must be diagnosed and corrected before
a battery is replaced and before a vehicle is returned to service. The service information for these systems has
been separated within this service manual to make it easier to locate the specific information you are seeking. How-
ever, when attempting to diagnose any of these systems, it is important that you keep their interdependency in
mind.

The diagnostic procedures used for the battery, starting, and charging systems include the most basic conventional
diagnostic methods, to the more sophisticated On-Board Diagnostics (OBD) built into the Powertrain Control Module
(PCM). Use of an induction-type milliampere ammeter, a volt/ohmmeter, a battery charger, a carbon pile rheostat
(load tester) and a 12-volt test lamp may be required. All OBD-sensed systems are monitored by the PCM. Each
monitored circuit is assigned a Diagnostic Trouble Code (DTC). The PCM will store a DTC in electronic memory for
any inoperative system it detects. (Refer to 8 - ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) for the
proper charging system on-board diagnostic test procedures.

MICRO 420 BATTERY TESTER

The Micro 420 automotive battery system tester is designed to help diagnose the cause of a defective battery.
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BAT-
TERY TESTER) for directions on using the Micro 420 battery tester.

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BATTERY SYSTEM

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