2003 DODGE RAM group 13

OPERATION
The wax pellet is located in a sealed container at
the spring end of the thermostat. When heated, the
pellet expands, overcoming closing spring tension
and water pump pressure to force the valve to open.
DIAGNOSIS AND TESTINGÐTHERMOSTAT
ON-BOARD DIAGNOSTICS
Allgasoline powered modelsare equipped with
On-Board Diagnostics for certain cooling system com-
ponents. Refer to On-Board Diagnostics (OBD) in the
Diagnosis section of this group for additional infor-
mation. If the powertrain control module (PCM)
detects low engine coolant temperature, it will record
a Diagnostic Trouble Code (DTC) in the PCM mem-
ory. Do not change a thermostat for lack of heat as
indicated by the instrument panel gauge or by poor
heater performance unless a DTC is present. Refer to
the Diagnosis section of this group for other probable
causes.
The DTC can also be accessed through the
DRBIIItscan tool. Refer to the appropriate Power-
train Diagnostic Procedures information for diagnos-
tic information and operation of the DRBIIItscan
tool.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE COOLING SYSTEM HOT
AND PRESSURIZED. SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
Do not waste reusable coolant. If the solution is
clean, drain the coolant into a clean container for
reuse.
If the thermostat is being replaced, be sure that
the replacement is the specified thermostat for the
vehicle model and engine type.
Factory installed thermostat housings on 5.9L
engine is installed on a gasket with an anti-stick
coating. This will aid in gasket removal and clean-up.
(1) Disconnect the negative battery cable.
(2) Drain the cooling system until the coolant level
is below the thermostat (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Air Conditioned vehicles: Remove the support
bracket (generator mounting bracket-to-intake mani-
fold) located near the rear of the generator (Fig. 19).
NOTE: On air conditioning equipped vehicles, the
generator must be partially removed.
(4) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 20).
(5) Remove the generator mounting bolts. Do not
remove any of the wiring at the generator. If
equipped with 4WD, unplug the 4WD indicator lamp
wiring harness (located near rear of generator).
(6) Remove the generator. Position the generator
to gain access for the thermostat gasket removal.
Fig. 18 Thermostat - 5.7L/5.9L Gas Powered
Engines
1 - THERMOSTAT HOUSING
2 - GASKET
3 - INTAKE MANIFOLD
4 - THERMOSTAT
5 - MACHINED GROOVE
Fig. 19 Generator Support Bracket ± 5.9L Engine
1 - IDLER PULLEY BUSHING
2 - A/C AND/OR GENERATOR MOUNTING BRACKET
3 - IDLER PULLEY
4 - SCREW AND WASHER
7 - 48 ENGINEDR
ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)

emissions and crankcase condensation. This conden-
sation can result in sludge formation.
OPERATION
The wax pellet is located in a sealed container at
the spring end of the thermostat. When heated, the
pellet expands, overcoming closing spring tension
and water pump pressure to force the valve to open.
DIAGNOSIS AND TESTINGÐTHERMOSTAT
ON-BOARD DIAGNOSTICS
Allgasoline powered modelsare equipped with
On-Board Diagnostics for certain cooling system com-
ponents. Refer to On-Board Diagnostics (OBD) in the
Diagnosis section of this group for additional infor-
mation. If the powertrain control module (PCM)
detects low engine coolant temperature, it will record
a Diagnostic Trouble Code (DTC) in the PCM mem-
ory. Do not change a thermostat for lack of heat as
indicated by the instrument panel gauge or by poor
heater performance unless a DTC is present. Refer tothe Diagnosis section of this group for other probable
causes.
The DTC can also be accessed through the
DRBIIItscan tool. Refer to the appropriate Power-
train Diagnostic Procedures information for diagnos-
tic information and operation of the DRBIIItscan
tool.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE COOLING SYSTEM HOT
AND PRESSURIZED. SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
Do not waste reusable coolant. If the solution is
clean, drain the coolant into a clean container for
reuse.
If the thermostat is being replaced, be sure that
the replacement is the specified thermostat for the
vehicle model and engine type.
(1) Disconnect the negative battery cable.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Raise and support the vehicle.
(4) Remove the splash shield.
(5) Remove the lower radiator hose clamp and the
lower radiator hose at the thermostat housing.
(6) Remove the thermostat housing mounting
bolts, thermostat housing and thermostat (Fig. 26).
INSTALLATION
(1) Clean the mating areas of the timing chain
cover and the thermostat housing.
(2) Install the thermostat (spring side down) into
the recessed machined groove on the timing chain
cover (Fig. 26).
(3) Position the thermostat housing on the timing
chain cover.
(4) Install the housing-to-timing chain cover bolts.
Tighten the bolts to 13 N´m (112 in. lbs.).
CAUTION: The housing must be tightened evenly
and the thermostat must be centered into the
recessed groove in the timimg chain cover. If not, it
may result in a cracked housing, damaged timing
chain cover threads or coolant leaks.
(5) Install the lower radiator hose on the thermo-
stat housing.
(6) Install the splash shield.
(7) Lower the vehicle.
(8) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(9) Connect negative battery cable.
(10) Start and warm the engine. Check for leaks.
Fig. 25 Thermostat Cross Section View 3.7L/4.7L
1 - FROM HEATER AND DEGAS CONTAINER
2 - FROM RADIATOR
3 - TO WATER PUMP
4 - ENGINE BYPASS
5 - THERMOSTAT
DRENGINE 7 - 51
ENGINE COOLANT THERMOSTAT - 3.7L/4.7L (Continued)

INSPECTION
Visually inspect the water pump and replace if it
has any of the following conditions:
²The body is cracked or damaged
²Water leaks from the shaft seal. This is evident
by traces of coolant below the vent hole
²Loose or rough turning bearing.
²Impeller rubbing the pump body
INSTALLATION
(1) Install new O-ring seal in groove on water
pump (Fig. 51).
(2) Install water pump. Tighten mounting bolts to
24 N´m (18 ft. lbs.) torque.
(3) Install accessory drive belt. Refer to procedure
in this group.
(4) Install the bolt retaining the wiring harness
near top of water pump.
(5) Fill cooling system. Refer to Refilling Cooling
System in this section.
(6) Connect both battery cables.
(7) Start and warm the engine. Check for leaks.
WATER PUMP INLET TUBE -
5.9L
REMOVAL
REMOVAL - WATER PUMP BYPASS HOSE
WITH AIR CONDITIONING
If equipped with A/C, the generator and A/C com-
pressor along with their common mounting bracket
(Fig. 52) must be partially removed. Removing thegenerator or A/C compressor from their mounting
bracket is not necessary. Also, discharging the A/C
system is not necessary.Do notremove any refriger-
ant lines from A/C compressor.
WARNING: THE A/C SYSTEM IS UNDER PRESSURE
EVEN WITH THE ENGINE OFF. REFER TO REFRIG-
ERANT WARNINGS IN SECTION 24 - HEATING AND
AIR CONDITIONING.
(1) Disconnect the negative battery cable.
(2) Partially drain the cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).Do not
waste reusable coolant. If the solution is clean, drain
the coolant into a clean container for reuse.
(3) Remove the upper radiator hose clamp at the
radiator. A special clamp tool must be used to remove
the constant tension clamps. Removethe hose at the
radiator.
(4) Unplug the wiring harness from the A/C com-
pressor.
(5) Remove the air cleaner assembly.
(6) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(7) The drive belt idler pulley must be removed to
gain access to one of the A/C compressor/generator
bracket mounting bolts. Remove the idler pulley bolt
and remove idler pulley (Fig. 53).
(8) Remove the engine oil dipstick tube mounting
bolt at the side of the A/C-generator mounting
bracket.
(9) Disconnect the throttle body control cables.
Fig. 51 Pump O-ring Seal
1 - O-RING SEAL
2 - GROOVE
3 - WATER PUMP
Fig. 52 Generator - A/C Compressor Mounting
Bracket - Typical
7 - 68 ENGINEDR
WATER PUMP - 5.9L DIESEL (Continued)

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 (if equipped)
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 (if equipped) for an indication of the battery
condition. If the battery is discharged, charge as
required. Refer to Standard Procedures for the
proper battery built-in indicator test procedures. Also
refer to Standard Procedures for the proper battery
charging procedures.
SPECIFICATIONS
The battery Group Size number, the Cold Cranking
Amperage (CCA) rating, and the Reserve Capacity
(RC) rating or Ampere-Hours (AH) rating can befound on the original equipment battery label. Be
certain that a replacement battery has the correct
Group Size number, as well as CCA, and RC or AH
ratings that equal or exceed the original equipment
specification for the vehicle being serviced. Battery
sizes and ratings are discussed in more detail below.
²Group Size- The outside dimensions and ter-
minal placement of the battery conform to standards
established by the Battery Council International
(BCI). Each battery is assigned a BCI Group Size
number to help identify a correctly-sized replace-
ment.
²Cold Cranking Amperage- The Cold Crank-
ing Amperage (CCA) rating specifies how much cur-
rent (in amperes) the battery can deliver for thirty
seconds at -18É C (0É F). Terminal voltage must not
fall below 7.2 volts during or after the thirty second
discharge period. The CCA required is generally
higher as engine displacement increases, depending
also upon the starter current draw requirements.
²Reserve Capacity- The Reserve Capacity (RC)
rating specifies the time (in minutes) it takes for bat-
tery terminal voltage to fall below 10.5 volts, at a
discharge rate of 25 amperes. RC is determined with
the battery fully-charged at 26.7É C (80É F). This rat-
ing estimates how long the battery might last after a
charging system failure, under minimum electrical
load.
²Ampere-Hours- The Ampere-Hours (AH) rat-
ing specifies the current (in amperes) that a battery
can deliver steadily for twenty hours, with the volt-
age in the battery not falling below 10.5 volts. This
rating is also sometimes identified as the twenty-
hour discharge rating.
BATTERY CLASSIFICATIONS & RATINGS
Part NumberBCI Group Size
ClassificationCold Cranking
AmperageReserve
CapacityAmpere -
HoursLoad Test
Amperage
56029449AB 65 600 120 Minutes 66 300
56029451AB 65 750 150 Minutes 75 375
56028450AA 65 600 120 Minutes 66 300
56028452AA 65 750 150 Minutes 75 375
56028452AB 65 700 130 Minutes 70 350
56029396AA 65 700 130 Minutes 70 350
56029382AA 65 700 130 Minutes 70 350
8F - 6 BATTERY SYSTEMDR
BATTERY SYSTEM (Continued)

SPECIAL TOOLS
BATTERY SYSTEM SPECIAL TOOLS
BATTERY
DESCRIPTION
A large capacity, low-maintenance storage battery
(Fig. 4) is standard factory-installed equipment on
this model. Models equipped with a diesel engine
must utilize two 12-volt batteries connected in paral-
lel. Male post type terminals made of a soft lead
material protrude from the top of the molded plastic
battery case to provide the means for connecting the
battery to the vehicle electrical system. The battery
positive terminal post is physically larger in diameter
than the negative terminal post to ensure proper bat-
tery connection. The lettersPOSandNEGare also
molded into the top of the battery case adjacent to
their respective positive and negative terminal posts
for identification confirmation. Refer to Battery
Cables for more information on the battery cables
that connect the battery to the vehicle electrical sys-
tem.
The battery is made up of six individual cells that
are connected in series. Each cell contains positively
charged plate groups that are connected with lead
straps to the positive terminal post, and negatively
charged plate groups that are connected with lead
straps to the negative terminal post. Each plate con-
sists of a stiff mesh framework or grid coated with
lead dioxide (positive plate) or sponge lead (negative
plate). Insulators or plate separators made of a non-
conductive material are inserted between the positive
and negative plates to prevent them from contacting
or shorting against one another. These dissimilar
metal plates are submerged in a sulfuric acid and
water solution called an electrolyte.
The factory-installed battery has a built-in test
indicator (hydrometer). The color visible in the sight
glass of the indicator will reveal the battery condi-
tion. Refer to Standard Procedures for the proper
built-in indicator test procedures.The factory-in-
stalled low-maintenance battery has non-re-
movable battery cell caps.Water cannot be added
to this battery. The battery is not sealed and has
vent holes in the cell caps. The chemical composition
of the metal coated plates within the low-mainte-
nance battery reduces battery gassing and water
loss, at normal charge and discharge rates. There-
fore, the battery should not require additional water
in normal service. Rapid loss of electrolyte can be
caused by an overcharging condition.
DIAGNOSIS AND TESTING - BATTERY
The battery must be completely charged and the
terminals should be properly cleaned and inspected
before diagnostic procedures are performed. Refer to
Battery System Cleaning for the proper cleaning pro-
cedures, and Battery System Inspection for the
proper battery inspection procedures. Refer to Stan-
dard Procedures for the proper battery charging pro-
cedures.
Micro 420 Battery Tester
Fig. 4 Low-Maintenance Battery - Typical
1 - POSITIVE POST
2 - VENT
3 - CELL CAP
4 - TEST INDICATOR (IF EQUIPPED)
5 - CELL CAP
6 - VENT
7 - NEGATIVE POST
8 - GREEN BALL
9 - ELECTROLYTE LEVEL
10 - PLATE GROUPS
11 - LOW-MAINTENANCE BATTERY
DRBATTERY SYSTEM 8F - 7
BATTERY SYSTEM (Continued)

between the battery positive cable terminal clamp
and the battery positive terminal post.
NOTE: If the vehicle is equipped with two 12v bat-
teries, step #2 must be performed twice, once for
each battery.
(3) Connect the voltmeter to measure between the
battery positive cable terminal clamp and the starter
solenoid B(+) terminal stud (Fig. 13). Rotate and hold
the ignition switch in the Start position. Observe the
voltmeter. If the reading is above 0.2 volt, clean and
tighten the battery positive cable eyelet terminal con-
nection at the starter solenoid B(+) terminal stud.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery positive cable.
NOTE: If the vehicle is equipped with two 12v bat-
teries, step #3 must be performed twice, once for
each battery.
(4) Connect the voltmeter to measure between the
battery negative cable terminal clamp and a good
clean ground on the engine block (Fig. 14). Rotate
and hold the ignition switch in the Start position.
Observe the voltmeter. If the reading is above 0.2
volt, clean and tighten the battery negative cable
eyelet terminal connection to the engine block.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery negative cable.
NOTE: If the vehicle is equipped with two 12v bat-
teries, step #4 must be performed twice, once for
each battery.
REMOVAL
(1) Turn the ignition switch to the Off position. Be
certain that all electrical accessories are turned off.
(2) Disconnect and isolate the remote battery neg-
ative cable terminal.
(3) Remove the battery from the vehicle. Refer to
the procedure in this group.
(4) One at a time, trace the battery cable retaining
pushpins, fasteners and routing clips until the cable
is free from the vehicle.
(5) Remove the battery cable from the engine com-
partment.
Fig. 12 Test Battery Positive Connection Resistance
- Typical
1 - VOLTMETER
2 - BATTERY
Fig. 13 Test Battery Positive Cable Resistance -
Typical
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
Fig. 14 Test Ground Circuit
1 - VOLTMETER
2 - BATTERY
3 - ENGINE GROUND
8F - 16 BATTERY SYSTEMDR
BATTERY CABLES (Continued)

INSTALLATION
(1) Position the battery cable in the engine com-
partment.
(2) One at a time, install the battery cable retain-
ing pushpins, fasteners and routing clips until the
cable is installed exactly where it was in the vehicle.
Refer to Wiring for illustrations.
(3) Install the battery in the vehicle. Refer to the
procedure in this group.
(4) Connect the battery negative cable terminal.
BATTERY TRAY
DESCRIPTION
The molded plastic tray battery tray is located in
the left front corner of the engine compartment. On
this model, the battery tray also provides an anchor
point for the anti-lock brake controller, cruise control
servo (if equipped) and the integrated power module
(Fig. 15). The battery hold down hardware is con-
tained within the battery tray. A hole in the bottom
of the battery tray is fitted with a battery tempera-
ture sensor. Refer to Charging System for more infor-
mation on the battery temperature sensor.
OPERATION
The battery tray and the battery hold down hard-
ware combine to secure and stabilize the battery in
the engine compartment, which prevents battery
movement during even the most extreme vehicle
operation. Unrestrained battery movement during
vehicle operation could result in damage to the vehi-
cle, the battery, or both.
REMOVAL
LEFT SIDE
(1) Remove the battery from the battery tray
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BAT-
TERY - REMOVAL).
(2) Remove the integrated power module (Refer to
8 - ELECTRICAL/POWER DISTRIBUTION/INTEL-
LIGENT POWER MODULE - REMOVAL).
(3) Disconnect the wire harness retainers from the
battery tray assembly.
(4) Remove the anti-lock brake controller (if
equipped) retaining bolts and support the brake con-
troller with mechanics wire. It is not necessary to
completely remove the anti-lock brake control unit.
(5) Remove the left front wheelhouse splash shiel-
d(Refer to 23 - BODY/EXTERIOR/LF WHEEL-
HOUSE SPLASH SHIELD - REMOVAL).
Fig. 15 DR Battery Tray
1 - BATTERY TRAY ASSEMBLY
2 - BATTERY TEMPERATURE SENSOR
3 - ANTI-LOCK BRAKE CONTROLLER MOUNTING LOCATION
4 - INTEGRATED POWER MODULE MOUNTING SANCTION
Fig. 16 Lower Battery Tray Retaining Bolts
1 - BATTERY TRAY ASSEMBLY
2 - BATTERY TRAY RETAINING BOLTS
3 - CRUISE CONTROL SERVO
DRBATTERY SYSTEM 8F - 17
BATTERY CABLES (Continued)

²a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test in 8, Battery for more information.
INSPECTION
The PCM (Powertrain Control Module), or ECM
(Diesel) monitors critical input and output circuits of
the charging system, making sure they are opera-
tional. A Diagnostic Trouble Code (DTC) is assigned
to each input and output circuit monitored by the
On-Board Diagnostic (OBD) system. Some charging
system circuits are checked continuously, and some
are checked only under certain conditions.
Refer to Diagnostic Trouble Codes in; Powertrain
Control Module; Electronic Control Modules for more
DTC information. This will include a complete list of
DTC's including DTC's for the charging system.
To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRBtscan tool. Per-
form the following inspections before attaching the
scan tool.
(1) Inspect the battery condition. Refer to 8, Bat-
tery for procedures.(2) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter
solenoid and relay. They should be clean and tight.
Repair as required.
(3) Inspect all fuses in both the fuseblock and
Power Distribution Center (PDC) for tightness in
receptacles. They should be properly installed and
tight. Repair or replace as required.
(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
torque specifications.
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications in 7, Cooling System.
(6) Inspect automatic belt tensioner (if equipped).
Refer to 7, Cooling System for information.
(7) Inspect generator electrical connections at gen-
erator field, battery output, and ground terminal (if
equipped). Also check generator ground wire connec-
tion at engine (if equipped). They should all be clean
and tight. Repair as required.
SPECIFICATIONS
GENERATOR RATINGS
TYPE PART NUMBER RATED SAE AMPS ENGINES
DENSO 56029700AA 136 3.7L / 4.7L
DENSO 56029701AA 136 5.9L Gas
BOSCH 56041120AC 136 3.7L / 4.7L
BOSCH 56028238AB 136 5.9L Gas
DENSO 56028560AA 136 8.0L
DENSO 56028696AA 136 5.7L Gas/5.9L Diesel
BOSCH 56028699AA 136 5.7L Gas/5.9L Diesel
SPECIFICATIONS - TORQUE - GENERATOR /
CHARGING SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Generator Mounting Bolts - 5.7L 41 30 -
Generator Support Bracket
Bolt/Nuts - 5.7L41 30 -
Generator Mounting Bolts - 8.0L 41 30 -
Generator Upper Mounting Bolt -
5.9L Diesel Engine41 30 -
Generator Upper Mounting Bolt -
5.9L Gas Engine41 30 -
8F - 20 CHARGINGDR
CHARGING (Continued)