2002 DODGE RAM battery

RIGHT SEAT HEATER INOPERATIVE
(1) If a heated seat heats but one or both indicator
lamps (LED's) on the heated seat switch fail to illu-
minate, check the driver circuit with the inoperative
LED for a short to ground. If OK, replace the heated
seat switch. If NOT OK repair the short to ground as
required and than replace the heated seat switch.
NOTE: IF THE RIGHT SEAT CUSHION IS ALREADY
WARM THE FOLLOWING STEP WILL NOT PROVE
CONCLUSIVE.
(2) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #3 for battery voltage when the right heated
seat switch is turned ªONº, voltage should be
present, If OK go to Step 3 If NOT OK, test the right
heated seat switch (Refer to 8 - ELECTRICAL/
HEATED SEATS/PASSENGER HEATED SEAT
SWITCH - DIAGNOSIS AND TESTING). If the
switch tests OK, check for continuity between the
switch and control module on the MUX circuit, If OK
replace the heated seat control module. If NOT OK,
repair the open or shorted MUX circuit as required.
NOTE: BE CERTAIN THE BATTERY IS FULLY
CHARGED BEFORE TESTING. FAILURE TO DO SO
CAN RESULT IN INCORRECT READINGS.
(3) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #10 for battery voltage, while observing the
voltmeter depress the right heated seat switchlow
setting twice, voltage should toggle between
approx.12v and 8v, If OK go to Step 4. If NOT OK
check for continuity between the switch and control
module on the low heat driver circuit, If OK replace
the heated seat control module.
(4) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #11 for battery voltage, while observing the
voltmeter depress the right heated seat switchhigh
setting twice, voltage should toggle between
approx.12v and 8v, If OK go to Step 5. If NOT OK
check for continuity between the switch and control
module on the high heat driver circuit, If OK replace
the heated seat control module.
(5) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #2 for approx. 5v, voltage should be present, If
OK go to Step 6. If NOT OK replace the heated seat
control module.
(6) Back-probe the heated seat module wire har-
ness connector, do not disconnect. Check cavity #7 for
a range in voltage from 1.72v (warm seat) ± 3.0v
(cold seat). It should be within this range, If OK
replace the heated seat module. If NOT OK test theHeated Seat Sensor. If NOT OK, replace the right
heated seat element and sensor assembly. If the
heated seat sensor tests OK, check for continuity
between the right heated seat cushion connector and
control module connector on the 5v supply circuit, If
NOT OK, repair the open or shorted 5v supply circuit
as required. If OK check for continuity between the
right heated seat cushion connector and control mod-
ule connector on the temperature sensor input cir-
cuit. If NOT OK, repair the open or shorted
temperature sensor input circuit as required. If OK
replace the heated seat control module.
LEFT SEAT HEATER INOPERATIVE
(1) If a heated seat heats but one or both indicator
lamps (LED's) on the heated seat switch fail to illu-
minate, check the driver circuit with the inoperative
LED for a short to ground. If OK, replace the heated
seat switch. If NOT OK repair the short to ground as
required and than replace the heated seat switch.
NOTE: IF THE LEFT SEAT CUSHION IS ALREADY
WARM THE FOLLOWING STEP WILL NOT PROVE
CONCLUSIVE.
(2) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #5 for battery voltage when the left heated
seat switch is turned ªONº, voltage should be
present, If OK go to Step 3 If NOT OK, test the left
heated seat switch (Refer to 8 - ELECTRICAL/
HEATED SEATS/DRIVER HEATED SEAT SWITCH
- DIAGNOSIS AND TESTING). If the switch tests
OK, check for continuity between the switch and con-
trol module on the MUX circuit, If OK replace the
heated seat control module. If NOT OK, repair the
open or shorted MUX circuit as required.
(3) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #12 for battery voltage, while observing the
voltmeter depress the left heated seat switchlow
setting twice, voltage should toggle between
approx.12v and 8v, If OK go to Step 4. If NOT OK
check for continuity between the switch and control
module on the low heat driver circuit, If OK replace
the heated seat control module.
(4) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #14 for battery voltage, while observing the
voltmeter depress the left heated seat switchhigh
setting twice, voltage should toggle between
approx.12v and 8v, If OK go to Step 5. If NOT OK
check for continuity between the switch and control
module on the high heat driver circuit, If OK replace
the heated seat control module.
8E - 22 ELECTRONIC CONTROL MODULESBR/BE
HEATED SEAT MODULE (Continued)

(5) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #2 for approx. 5v, 5 voltage should be present,
If OK go to Step 6. If NOT OK replace the heated
seat control module.
(6) Back-probe the heated seat module wire har-
ness connector, do not disconnect. Check cavity #8 for
a range in voltage from 1.72v (warm seat) ± 3.0v
(cold seat). It should be within this range, If OK
replace the heated seat control module. If NOT OK,
test the Heated Seat Sensor. If NOT OK, replace the
left heated seat element and sensor assembly. If the
heated seat sensor tests OK, check for continuity
between the left heated seat cushion connector and
control module connector on the 5v supply circuit, If
NOT OK, repair the open or shorted 5v supply circuit
as required. If OK check for continuity between the
left heated seat cushion connector and control mod-
ule connector on the temperature sensor input cir-
cuit. If NOT OK, repair the open or shorted
temperature sensor input circuit as required. If OK
replace the heated seat control module.
BOTH SEATS INOPERATIVE
If both seats (driver and passenger) fail to heat
and the indicator lamps on the heated seat switches
for both seats fail to operate, test the heated seat
relay and/or fuses. Refer toRelay Diagnosis and
Testingin the Power Distribution section for heated
seat relay diagnosis and testing procedures. If the
heated seat relay checks OK, go to Step 1.
(1) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check for
continuity between the ground circuit cavity #13 of
the heated seat module connector and a good ground.
If OK go to Step 2. If NOT OK, repair the open or
shorted ground circuit as required.
(2) Back-probe the heated seat module wire har-
ness connector (Fig. 20) , do not disconnect. Check
cavity #4 and #6 for battery voltage, voltage should
be present, If OK go to Step 3. If NOT OK repair the
open or shorted fused B(+) circuit as required.
(3) Back-probe the heated seat module wire har-
ness connector, do not disconnect. Check cavity #2 for
approx. 5v, voltage should be present, replace the
heated seat control module with a known good mod-
ule and verify system operation.
REMOVAL
(1) Working under the center front seat console,
cut the tiestrap and remove the two push-on retain-
ers that secure the mounting tabs of the heated seat
module to the of the mounting bracket.
(2) Position the driver seat to the full forward and
inclined position and working under the center of the
front seat, from behind the seat, disconnect the seat
wire harness connector from the connector receptacle
on the back of the heated seat module (Fig. 21).
(3) Remove the heated seat module from under the
front seat.
INSTALLATION
(1) Working under the front seat connect the seat
wire harness connector to the connector receptacle on
the back of the heated seat module.
(2) Position the driver seat in the full rearward
and reclined position, and working under the front of
the seat, install the two push-on retainers onto the
heated seat module mounting tabs to secure the mod-
ule to the top of the mounting bracket or install
tiestrap.
Fig. 21 Heated Seat Module Remove/Install
1 - MOUNTING BRACKET
2 - HEATED SEAT MODULE
3 - MOUNTING TABS
4 - PUSH-ON RETAINERS
BR/BEELECTRONIC CONTROL MODULES 8E - 23
HEATED SEAT MODULE (Continued)

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING.............................. 25STARTING............................... 31
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................6
SPECIFICATIONS
BATTERY............................6
SPECIAL TOOLS........................7
BATTERY
DESCRIPTION..........................7
DIAGNOSIS AND TESTING - BATTERY.......7
STANDARD PROCEDURE
STANDARD PROCEDURE - BATTERY
CHARGING...........................8
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST.....................10
STANDARD PROCEDURE - HYDROMETER
TEST...............................11
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................12
STANDARD PROCEDURE - LOAD TEST....12
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................13
STANDARD PROCEDURE - USING
MIDTRONICS ELECTRICAL TESTER.......15REMOVAL.............................16
INSTALLATION.........................16
BATTERY HOLDDOWN
DESCRIPTION.........................17
OPERATION...........................17
REMOVAL.............................17
INSTALLATION.........................18
BATTERY CABLE
DESCRIPTION.........................18
OPERATION...........................18
DIAGNOSIS AND TESTING - BATTERY
CABLES............................19
REMOVAL
POSITIVE CABLE REMOVAL - GASOLINE
ENGINE.............................21
NEGATIVE CABLE REMOVAL - GASOLINE
ENGINE.............................22
INSTALLATION
POSITIVE CABLE INSTALLATION -
GASOLINE ENGINE....................22
NEGATIVE CABLE INSTALLATION -
GASOLINE ENGINE....................22
BATTERY TRAY
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................24
BATTERY SYSTEM
DESCRIPTION
A single 12-volt battery system is standard factory-
installed equipment on gasoline engine equipped
models. Models equipped with a diesel engine utilize
two 12-volt batteries connected in parallel. All of thecomponents of the battery system are located within
the engine compartment of the vehicle. The service
information for the battery system in this vehicle
covers the following related components, which are
covered in further detail elsewhere in this service
manual:
BR/BEENGINE SYSTEMS 8F - 1

²Battery- The storage battery provides a reli-
able means of storing a renewable source of electrical
energy within the vehicle.
²Battery Cable- The battery cables connect the
battery terminal posts to the vehicle electrical sys-
tem.
²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
²Battery Tray- The battery tray provides a
secure mounting location in the vehicle for the bat-
tery and an anchor point for the battery holddown
hardware.
For battery system maintenance schedules and
jump starting procedures, see the owner's manual in
the vehicle glove box. Optionally, refer to Lubrication
and Maintenance for the recommended battery main-
tenance schedules and for the proper battery jump
starting procedures. While battery charging can be
considered a maintenance procedure, the battery
charging procedures and related information are
located in the standard procedures section of this ser-
vice manual. This was done because the battery must
be fully-charged before any battery system diagnosis
or testing procedures can be performed. Refer to
Standard procedures for the proper battery charging
procedures.
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 to operate many of the other vehicle acces-
sory 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 sys-
tem 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 complete 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 thor-
oughly tested and inspected any time a battery needs
to be charged or replaced. The cause of abnormal bat-
tery 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 eas-
ier to locate the specific information you are seeking.
However, when attempting to diagnose any of these
systems, it is important that you keep their interde-
pendency 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/ohmme-
ter, 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 Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for any failure it detects. Refer to
Charging System for the proper charging system on-
board diagnostic test procedures.
MIDTRONICS ELECTRICAL SYSTEM TESTER
The Midtronicstautomotive battery and charging
system tester is designed to help the dealership tech-
nicians diagnose the cause of a defective battery or
charging system. Follow the instruction manual sup-
plied with the tester to properly diagnose a vehicle. If
the instruction manual is not available refer to the
standard procedure in this section, which includes
the directions for using the midtronics electrical sys-
tem tester.
8F - 2 BATTERY SYSTEMBR/BE
BATTERY SYSTEM (Continued)

BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY SEEMS
WEAK OR DEAD WHEN
ATTEMPTING TO START
THE ENGINE.1. The electrical system
ignition-off draw is excessive.1. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the excessive ignition-off
draw, as required.
2. The charging system is
faulty.2. Determine if the charging system is performing
to specifications using the Midtronics battery and
charging system tester. Refer to Charging System
for additional charging system diagnosis and
testing procedures. Repair the faulty charging
system, as required.
3. The battery is discharged. 3. Determine the battery state-of-charge using the
Midtronics battery and charging system tester.
Refer to the Standard Procedures in this section
for additional test procedures. Charge the faulty
battery, as required.
4. The battery terminal
connections are loose or
corroded.4. Refer to Battery Cables for the proper battery
cable diagnosis and testing procedures. Clean
and tighten the battery terminal connections, as
required.
5. The battery has an
incorrect size or rating for
this vehicle.5. Refer to Battery System Specifications for the
proper size and rating. Replace an incorrect
battery, as required.
6. The battery is faulty. 6. Determine the battery cranking capacity using
the Midtronics battery and charging system tester.
Refer to the Standard Procedures in this section
for additional test procedures. Replace the faulty
battery, as required.
7. The starting system is
faulty.7. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
8. The battery is physically
damaged.8. Inspect the battery for loose terminal posts or a
cracked and leaking case. Replace the damaged
battery, as required.
BR/BEBATTERY SYSTEM 8F - 3
BATTERY SYSTEM (Continued)

BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY STATE OF
CHARGE CANNOT BE
MAINTAINED.1. The battery has an
incorrect size or rating for
this vehicle.1. Refer to Battery System Specifications for the
proper specifications. Replace an incorrect
battery, as required.
2. The battery terminal
connections are loose or
corroded.2. Refer to Battery Cable for the proper cable
diagnosis and testing procedures. Clean and
tighten the battery terminal connections, as
required.
3. The electrical system
ignition-off draw is excessive.3. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the faulty electrical system, as
required.
4. The battery is faulty. 4. Test the battery using the Midtronics battery
and charging system tester. Refer to Standard
Procedures for additional test procedures.
Replace the faulty battery, as required.
5. The starting system is
faulty.5. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
6. The charging system is
faulty.6. Determine if the charging system is performing
to specifications using the Midtronics battery and
charging system tester.. Refer to Charging
System for additional charging system diagnosis
and testing procedures. Repair the faulty charging
system, as required.
7. Electrical loads exceed the
output of the charging
system.7. Inspect the vehicle for aftermarket electrical
equipment which might cause excessive electrical
loads.
8. Slow driving or prolonged
idling with high-amperage
draw systems in use.8. Advise the vehicle operator, as required.
THE BATTERY WILL NOT
ACCEPT A CHARGE.1. The battery is faulty. 1. Test the battery using the Midtronics battery
and charging system tester.. Charge or replace
the faulty battery, as required.
8F - 4 BATTERY SYSTEMBR/BE
BATTERY SYSTEM (Continued)

ABNORMAL BATTERY DISCHARGING
Any of the following conditions can result in abnor-
mal battery discharging:
²A faulty or incorrect charging system compo-
nent. Refer to Charging System for the proper charg-
ing system diagnosis and testing procedures.
²A faulty or incorrect battery. Refer to Standard
Procedures for the proper battery diagnosis and test-
ing procedures. Refer to Battery System Specifica-
tions for the proper specifications.
²A faulty circuit or component causing excessive
ignition-off draw.
²Electrical loads that exceed the output of the
charging system. This can be due to equipment
installed after manufacture, or repeated short trip
use.
²A faulty or incorrect starting system component.
Refer to Starting System for the proper starting sys-
tem diagnosis and testing procedures.
²Corroded or loose battery posts and terminal
clamps.
²A loose or worn generator drive belt.
²Slow driving speeds (heavy traffic conditions) or
prolonged idling, with high-amperage draw systems
in use.
CLEANING
The following information details the recommended
cleaning procedures for the battery and related com-
ponents. In addition to the maintenance schedules
found in this service manual and the owner's man-
ual, it is recommended that these procedures be per-
formed any time the battery or related components
must be removed for vehicle service.
(1) Clean the battery cable terminal clamps of all
corrosion. Remove any corrosion using a wire brush
or a post and terminal cleaning tool, and a sodium
bicarbonate (baking soda) and warm water cleaning
solution (Fig. 1).
(2) Clean the battery tray and battery holddown
hardware of all corrosion. Remove any corrosion
using a wire brush and a sodium bicarbonate (baking
soda) and warm water cleaning solution. Paint any
exposed bare metal.
(3) If the removed battery is to be reinstalled,
clean the outside of the battery case and the top
cover with a sodium bicarbonate (baking soda) and
warm water cleaning solution using a stiff bristle
parts cleaning brush to remove any acid film (Fig. 2).
Rinse the battery with clean water. Ensure that the
cleaning solution does not enter the battery cells
through the vent holes. If the battery is being
replaced, refer to Battery System Specifications for
the factory-installed battery specifications. Confirm
that the replacement battery is the correct size and
has the correct ratings for the vehicle.
Fig. 1 Clean Battery Cable Terminal Clamp - Typical
1 - TERMINAL BRUSH
2 - BATTERY CABLE
Fig. 2 Clean Battery - Typical
1 - CLEANING BRUSH
2 - WARM WATER AND BAKING SODA SOLUTION
3 - BATTERY
BR/BEBATTERY SYSTEM 8F - 5
BATTERY SYSTEM (Continued)

(4) Clean the battery thermal guard with a sodium
bicarbonate (baking soda) and warm water cleaning
solution using a stiff bristle parts cleaning brush to
remove any acid film.
(5) Clean any corrosion from the battery terminal
posts with a wire brush or a post and terminal
cleaner, and a sodium bicarbonate (baking soda) and
warm water cleaning solution (Fig. 3).
INSPECTION
The following information details the recommended
inspection procedures for the battery and related
components. In addition to the maintenance sched-
ules found in this service manual and the owner's
manual, it is recommended that these procedures be
performed any time the battery or related compo-
nents must be removed for vehicle service.
(1) Inspect the battery cable terminal clamps for
damage. Replace any battery cable that has a dam-
aged or deformed terminal clamp.
(2) Inspect the battery tray and battery holddown
hardware for damage. Replace any damaged parts.
(3) Slide the thermal guard off of the battery case,
if equipped. Inspect the battery case for cracks or
other damage that could result in electrolyte leaks.
Also, check the battery terminal posts for looseness.
Batteries with damaged cases or loose terminal posts
must be replaced.
(4) Inspect the battery thermal guard for tears,
cracks, deformation or other damage. Replace any
battery thermal guard that has been damaged.(5) Inspect the battery built-in test indicator sight
glass for an indication of the battery condition. If the
battery is discharged, charge as required. (Refer to 8
- ELECTRICAL/BATTERY SYSTEM/BATTERY -
STANDARD PROCEDURE).
SPECIFICATIONS
BATTERY
Battery Classifications and Ratings
Part NumberBCI Group Size
ClassificationCold
Cranking
AmperageReserve
CapacityAmpere-HoursLoad Test
Amperage
56028375AA 27 600 120 Minutes 66 300
56028376AA 27 750 150 Minutes 75 375
Fig. 3 Clean Battery Terminal Post - Typical
1 - TERMINAL BRUSH
2 - BATTERY CABLE
3 - BATTERY
8F - 6 BATTERY SYSTEMBR/BE
BATTERY SYSTEM (Continued)