2003 DODGE RAM app

Fan speed is monitored by the ECM. A lack of fan
speed will set a DTC. Circuit concerns will also set
fan clutch DTC's.
Fan speed and duty cycle percent can be monitored
with the DRB III..
DIAGNOSIS AND TESTING - ELECTRONICLY
CONTOLLED VISCOUS FAN DRIVE
NOISE
NOTE: It is normal for fan noise to be louder (roar-
ing) when:
²Fan duty cycle high. This may occur when ambi-
ent (outside air temperature) is very high.
²Engine loads and temperatures are high such as
when towing a trailer.
²Cool silicone fluid within the fan drive unit is
being redistributed back to its normal disengaged
(warm) position. This can occur during the first 15
seconds to one minute after engine start-up on a cold
engine.
LEAKS
Viscous fan drive operation is not affected by small
oil stains near the drive bearing. If leakage appears
excessive, replace the fan drive unit.
ELECTRONICALLY CONTROLLED VISCOUS DRIVE
If the fan assembly free-wheels without drag (the
fan blades will revolve more than five turns when
spun by hand), replace the fan drive. This spin test
must be performed when the engine is cool.
For the following test, the cooling system must be
in good condition. It also will ensure against exces-
sively high coolant temperature.
The Electronic Viscous Fan drive can be tested
using the DRB III scan tool.
(1) Set the parking brake and verify the transmis-
sion is in park or neutral.
(2) Stat and allow engine to reach normal operat-
ing termeratures.
(3) With engine idling, connect the DRB III and
select appropraite model year and engine option.
(4) Lacate and select actuator tests, then select
PWM Viscous Fan.
(5) Monitor fan speed and duty cycle; verify that
the fan speed increments are proportional to the duty
cycle precentage during the actuation event.
CAUTION: Some engines equipped with serpentine
drive belts have reverse rotating fans and viscous
fan drives. They are marked with the word
REVERSE to designate their usage. Installation of
the wrong fan or viscous fan drive can result in
engine overheating.
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks, loose blades, or loose rivets that could
have resulted from excessive vibration. Replace fan
blade assembly if any of these conditions are
found.
RADIATOR
DESCRIPTION
The radiator is a aluminum cross-flow design with
horizontal tubes through the radiator core and verti-
cal plastic side tanks (Fig. 32).
This radiator does not contain an internal trans-
mission oil cooler
OPERATION
The radiator supplies sufficient heat transfer using
the cooling fins interlaced between the horizontal
tubes in the radiator core to cool the engine.
Fig. 31 Fan Blade/Viscous Fan Drive
1 - ELECTRICAL CONNECTOR
2 - VISCOUS FAN DRIVE
3 - FAN BLADE
4 - BOLT
5 - FAN DRIVE
7 - 56 ENGINEDR
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL (Continued)

NOTE: The radiator is equipped with one alignment
dowel on the bottom of the outlet tank and one
retaining bracket on the front side of the inlet tank.
Both features have rubber insulators attached to
them that must be present. The alignment dowel fits
into a hole at the bottom of the front end sheet
metal vertical support post and the support bracket
rests on top of the lower radiator closure tube.
CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and oil cooler fins should be
cleaned when an accumulation of debris has
occurred. With the engine cold, apply cold water and
compressed air to the back (engine side) of the radi-
ator to flush the radiator and/or oil coolers of debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position the fan shroud over the fan blades
rearward towards engine.
(2) Install the rubber insulators to the lower radi-
ator mounting features (alignment dowel and support
bracket at the lower part of the radiator).
(3) Lower the radiator into position while guiding
the alignment dowel into the vertical post bracket.
Position and seat the lower radiator support bracket
onto the lower radiator closure tube.
(4) Install the upper radiator mounting bolts.
Tighten bolts to 8.5 N´m (75 in. lbs.).
(5) Connect the lower radiator hose and install the
clamp in the proper position.
(6) Connect the power steering hoses to the power
steering oil cooler and install the clamps.
(7) Connect the transmission oil cooler lines to the
transmission oil cooler and install the secondary
latches.
(8) Position the fan shroud into the mounting clips
on the radiator tanks and secure with bolts. Tighten
the bolts to 8.5 N´m (75 in. lbs.).
(9) Secure the power steering hoses into the clip
on the lower fan shroud.
(10) Install the windshield washer reservoir tank
and connect the hose and electrical connector.
(11) Install coolant reserve/overflow container
hose(s) to radiator filler neck and secure properly
with clamps.
Fig. 33 Fan Shroud
1 - RADIATOR
2 - SCREWS
3 - FAN SHROUD
4 - SLIDE MOUNT
Fig. 34 Radiator
1 - SCREW
2 - SCREW
3 - LOWER MOUNT
4 - RADIATOR
5 - DRAINCOCK
6 -LOWER MOUNT
7 - 58 ENGINEDR
RADIATOR (Continued)

(6) Remove the power steering cooler mounting
bolts and position the power steering cooler out of
the way.
(7) Disconnect the transmission cooler lines at the
transmission. The transmission cooler will remain on
the radiator and can be removed as an assembly.
(8) Remove the lower shroud assembly and the
electronic viscous fan wiring from the upper shroud
assembly.
(9) Remove the two radiator upper mounting bolts
(Fig. 36).
(10) Lift radiator straight up and out of engine
compartment. The bottom of the radiator is equipped
with two alignment dowels that fit into holes in the
lower radiator support panel. Rubber biscuits (insu-
lators) are installed to these dowels. Take care not to
damage cooling fins or tubes on the radiator and air
conditioning condenser when removing.
CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and oil cooler fins should be
cleaned when an accumulation of debris has
occurred. With the engine cold, apply cold water and
compressed air to the back (engine side) of the radi-
ator to flush the radiator and/or oil coolers of debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Install rubber insulators to alignment dowels
at lower part of radiator.
(2) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(3) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(4) Connect both radiator hoses and install hose
clamps.
(5) Connect transmission cooler lines to radiator
tank. Inspect quick connect fittings for debris and
install until an audible ªclickº is heard. Pull apart to
verify connection.
(6) Position power steering cooler on the radiator
and tighten nuts to 8.5M´N (75 in. lbs.)
(7) Attach electronic viscous fan wiring to upper
shroud ands install lower shroud.
(8) Position coolant recover tank hose, washer bot-
tle hose and the positive battery cable into the clips
located on the top of the radiator.
(9) Install air box and turbocharger inlet hose.
Tighten clamps to 4 N´M (35 in. lbs.).
(10) Position heater controls tofull heatposition.
(11) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(12) Operate engine until it reaches normal tem-
perature. Check cooling system and automatic trans-
mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP
DESCRIPTION
All cooling systems are equipped with a pressure
cap (Fig. 37). For 5.9L engines, the pressure cap is
located on top of the radiator outlet tank. For the
3.7L/4.7L engines, the pressure cap is located on top
of the coolant degas container. The cap releases pres-
sure at some point within a range of 97-to-124 kPa
(14-to-18 psi). The pressure relief point (in pounds) is
engraved on top of the cap
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap contains a spring-
Fig. 36 Fan Shroud MountingÐ5.9L Diesel Engine
1 - RADIATOR SUPPORT
2 - UPPER FAN SHROUD
3 - BOLTS (2)
4 - LOWER FAN SHROUD
5 - RADIATOR
7 - 60 ENGINEDR
RADIATOR - 5.9L DIESEL (Continued)

(5) Remove the bolts attaching the transmission
cooler to the radiator.
(6) Remove oil cooler from the vehicle. Take care
not to damage the radiator core or transmission
cooler tubes.
DISASSEMBLY - 5.9L ONLY
NOTE: The transmission oil cooler uses an internal
thermostat to control transmission oil flow through
the cooler. This thermostat is servicable.
(1) Remove the transmission oil cooler (Refer to 7 -
COOLING/TRANSMISSION/TRANS COOLER -
REMOVAL).
(2) Remove the snap ring retaining the thermostat
end plug (Fig. 3).
(3) Remove the end plug, thermostat and spring
from transmission oil cooler (Fig. 3).
ASSEMBLY - 5.9L ONLY
(1) Throughly clean the thermostat bore on the
transmission oil cooler.
(2) Install the new spring, thermostat, end plug
and snap ring.(3) Install the transmission oil cooler (Refer to 7 -
COOLING/TRANSMISSION/TRANS COOLER -
INSTALLATION).
INSTALLATION
(1) Position the transmission cooler tubes to the
front of the radiator.
(2) Snap the transmission cooler tubes into the
clips on the side of the radiator tank.
(3) Install the transmission cooler attaching bolts.
Tighten the bolts to 16 N´m (140 in. lbs.).
(4) inspect the quick connect fittings for debris and
install the quick connect fitting on the cooler tube
until an audible ªclickº is heard. Pull apart the con-
nection to verify proper installation and install the
secondary latches.
(5) Connect the battery negative cable.
(6) Start the engine and check all fittings for
leaks.
(7) Check the fluid level in the automatic trans-
mission. Refer to the appropriate transmission sec-
tion(Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 45RFE/545RFE/FLUID - STANDARD
PROCEDURE) or(Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 46RE/FLUID - STAN-
DARD PROCEDURE).
TRANS COOLER - 5.9L DIESEL
DESCRIPTION
All diesel models equipped with an automatic
transmission are equipped with both a main water-
to-oil cooler and a separate air-to-oil cooler. Both cool-
Fig. 2 Cooling Module - 3.7L/4.7L/5.7L
1 - TRANS OIL COOLER
2 - TRANS OIL COOLER MOUNTING BOLT (3)
3 - POWER STEERING OIL COOLER
4 - POWER STEERING OIL COOLER MOUNTING BOLT
5 - TRANS OIL COOLER OUTLET
6 - TRANS OIL COOLER INLET
7 - COOLER LINE CLIP
8 - COOLER LINE CLIP
9 - RADIATOR
Fig. 3 Transmission Oil Cooler Thermostat
Removal/Installation
1 - THERMOSTAT HOUSING
2 - SPRING
3 - END PLUG
4 - SNAP RING
5 - THERMOSTAT
DRTRANSMISSION 7 - 73
TRANS COOLER (Continued)

AUDIO
TABLE OF CONTENTS
page page
AUDIO
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING - AUDIO..........2
AMPLIFIER
DESCRIPTION..........................3
OPERATION............................3
REMOVAL.............................3
INSTALLATION..........................4
ANTENNA BODY & CABLE
DESCRIPTION..........................4
OPERATION............................4
DIAGNOSIS AND TESTING - ANTENNA BODY
AND CABLE..........................4
REMOVAL.............................6
INSTALLATION..........................6
INSTRUMENT PANEL ANTENNA CABLE
REMOVAL.............................6
INSTALLATION..........................7
RADIO
DESCRIPTION..........................7OPERATION............................7
REMOVAL.............................7
INSTALLATION..........................8
RADIO NOISE SUPPRESSION GROUND STRAP
DESCRIPTION..........................8
OPERATION............................8
REMOVAL.............................9
INSTALLATION.........................10
REMOTE SWITCHES
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - REMOTE
SWITCHES..........................11
REMOVAL.............................12
INSTALLATION.........................12
SPEAKER
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - SPEAKER......13
REMOVAL.............................13
INSTALLATION.........................15
AUDIO
DESCRIPTION
An audio system is standard factory-installed
equipment on this model. Several combinations of
radio receivers and speaker systems are offered. The
audio system uses an ignition switched source of bat-
tery current so that the system will only operate
when the ignition switch is in the RUN or ACCES-
SORY positions.
The audio system includes the following compo-
nents:
²Antenna
²Power amplifier (with premium speaker system
only)
²Radio noise suppression components
²Radio receiver
²Remote radio switches (if equipped)
²Speakers
Certain functions and features of the audio system
rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munication Interface (PCI) bus network. The data
bus network allows the sharing of sensor informa-
tion. For diagnosis of these electronic modules or of
the data bus network, the use of a DRB IIItscan tooland the proper Diagnostic Procedures manual are
recommended.
Refer to the appropriate wiring information for
complete standard and premium audio system circuit
diagrams. The wiring information includes proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and location views for the various wire har-
ness connectors, splices, and grounds.
OPERATION
The audio system components are designed to pro-
vide audio entertainment and information through
the reception, tuning and amplification of locally
broadcast radio signals in both the Amplitude Modu-
lating (AM) and Frequency Modulating (FM) com-
mercial frequency ranges.
The audio system components operate on battery
current received through a fuse in the Integrated
Power Module (IPM) on a fused ignition switch out-
put (run-acc) circuit so that the system will only
operate when the ignition switch is in the Run or
Accessory positions.
On vehicles that are equipped with the optional
remote radio switches, the Instrument Cluster
receives hard wired resistor multiplexed inputs from
the remote radio switches. The programming in the
DRAUDIO 8A - 1

Instrument Cluster allows it to process those inputs
and send the proper messages to the radio receiver
over the Programmable Communication Interface
(PCI) bus network to control the radio volume up or
down, station seek up or down, preset station
advance, and mode advance functions.
Refer to the owner's manual for more information
on the features, use and operation of each of the
available audio systems.
DIAGNOSIS AND TESTING - AUDIO
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wireharness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
AUDIO SYSTEM DIAGNOSIS TABLE
CONDITION POSSIBLE CAUSES CORRECTION
NO AUDIO 1. Fuse faulty. 1. Check radio fuse and Ignition-Off Draw (IOD)
fuse in the Integrated Power Module (IPM).
Replace fuses, if required.
2. Radio/amplifier (if
equipped) connector faulty.2. Check for loose or corroded radio/amplifier
connector. Repair, if required.
3. Wiring faulty. 3. Check for shorted or open wires. Repair wiring,
if required.
4. Radio/amplifier (if
equipped) ground faulty.4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Radio/amplifier (if
equipped) faulty.5. Refer to appropriate Diagnostic Service
Manual.
6. Speakers faulty. 6. Replace speaker as necessary.
NO RADIO DISPLAY 1. Fuse faulty. 1. Check radio fuse and Ignition-Off Draw (IOD)
fuse in Integrated Power Module (IPM). Replace
fuses, if required.
2. Radio connector faulty. 2. Check for loose or corroded radio connector.
Repair, if required.
3. Wiring faulty. 3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Radio ground faulty. 4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Radio faulty. 5. Refer to appropriate Diagnostic Service
Manual.
8A - 2 AUDIODR
AUDIO (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
CLOCK WILL NOT KEEP
SET TIME1. Fuse faulty. 1. Check Ignition-Off Draw (IOD) fuse in the
Integrated Power Module (IPM). Replace fuse, if
required.
2. Radio connector faulty. 2. Check for loose or corroded radio connector.
Repair, if required.
3. Wiring faulty. 3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Radio ground faulty. 4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Radio faulty. 5. Refer to appropriate Diagnostic Service
Manual.
POOR RADIO RECEPTION 1. Antenna faulty. 1. (Refer to 8 - ELECTRICAL/AUDIO/ANTENNA
BODY & CABLE - DIAGNOSIS AND TESTING).
2. Radio ground faulty. 2. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
3. Radio noise suppression
faulty.3. Repair or replace ground strap as necessary.
4. Radio faulty. 4. Refer to appropriate Diagnostic Service
Manual.
NO/POOR TAPE
OPERATION1. Faulty tape. 1. Insert known good tape and test operation.
2. Foreign objects behind
tape door.2. Remove foreign objects and test operation.
3. Dirty cassette tape head. 3. Clean head with Mopar Cassette Head
Cleaner.
4. Faulty tape deck. 4. Exchange or replace radio, if required.
NO COMPACT DISC
OPERATION1. Faulty CD. 1. Insert known good CD and test operation.
2. Foreign material on CD. 2. Clean CD and test operation.
3. Condensation on CD or
optics.3. Allow temperature of vehicle interior to stabilize
and test operation.
4. Faulty CD player. 4. Refer to appropriate Diagnostic Service
Manual.
AMPLIFIER
DESCRIPTION
The optional Infinity premium speaker system
includes a separate Infinity audio power amplifier.
The amplifier is a six channel unit and is rated at
240 total output watts. The amplifier is located
behind the glove box.
OPERATION
The power amplifier electronically increases the
frequency response of the normal audio signal output
from the radio amplifier in order to improve the
acoustic performance of the speakers. On vehiclesequipped with an amplifier, the amplifier section of
the radio becomes a pre-amplifier.
The amplifier receives audio signal inputs for
speaker channels from the radio, then sends ampli-
fied audio outputs through six separate channels
with dedicated feed and return circuits to the indi-
vidual speakers.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove glove box (Refer to 23 - BODY/IN-
STRUMENT PANEL/GLOVE BOX - REMOVAL).
DRAUDIO 8A - 3
AUDIO (Continued)

DIAGNOSIS AND TESTING - REMOTE
SWITCHES
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Remove the remote radio switch(es) (Fig. 14)
from the steering wheel (Refer to 8 - ELECTRICAL/
AUDIO/REMOTE SWITCHES - REMOVAL).(2) Use an ohmmeter to check the switch resis-
tances as shown in the Remote Radio Switch Test
chart. If the remote radio switch resistances check
OK, go to Step 3. If not OK, replace the faulty
switch.
REMOTE RADIO SWITCH TEST TABLE
Switch Switch Position Resistance
Right
(White)Volume Up1.210 Kilohms
 1%
Right
(White)Volume Down3.010 Kilohms
 1%
Right
(White)Mode Advance0.0511 Kilohms
 1%
Left
(Black)Seek Up0.261 Kilohms
 1%
Left
(Black)Seek Down0.681 Kilohms
 1%
Left
(Black)Pre-Set Station
Advance0.162 Kilohms
 1%
(3) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for 5 volts
at the radio control mux circuit cavities of the steer-
ing wheel wire harness connectors for both remote
radio switches. If OK, go to Step 4. If not OK, repair
the open or shorted radio control mux circuit to the
Integrated Power Module (IPM) as required.
(4) Disconnect and isolate the battery negative
cable. Disconnect the 22-way instrument panel wire
harness connector from the IPM. Check for continu-
ity between the remote radio switch ground circuit
cavities of the steering wheel wire harness connec-
tors for both remote radio switches and a good
ground. There should be no continuity. If OK, go to
Step 5. If not OK, repair the shorted remote radio
switch ground circuit to the IPM as required.
(5) Check for continuity between the remote radio
switch ground circuit cavities of the steering wheel
wire harness connectors for both remote radio
switches and the 22-way instrument panel wire har-
ness connector for the IPM. There should be continu-
ity. If OK, refer to the proper Diagnostic Procedures
manual to test the IPM and the PCI data bus. If not
OK, repair the open remote radio switch ground cir-
cuit as required.
Fig. 14 Remote Radio Switches
1 - BLACK (LEFT) SWITCH
2 - WHITE (RIGHT) SWITCH
DRAUDIO 8A - 11
REMOTE SWITCHES (Continued)