2002 DODGE RAM length

CONDITION POSSIBLE CAUSES CORRECTION
NOISE (Objectional squeal, spueak,
or rumble is heard or felt while drive
belt is in operation)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Bearing noise 2. Locate and repair
3. Belt misalignment 3. Align belt/pulley(s)
4. Belt to pulley mismatch 4. Install correct belt
5. Driven component induced
vibration5. Locate defective driven
component and repair
TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)1. Tension sheeting contacting
stationary object1. Correct rubbing condition
2. Excessive heat causing woven
fabric to age2. Replace belt
3. Tension sheeting splice has
fractured3. Replace belt
CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Belt contacting stationary object 2. Replace belt
3. Pulley(s) out of tolerance 3. Replace pulley
4. Insufficient adhesion between
tensile member and rubber matrix4. Replace belt
REMOVAL
Drive belts are equipped with a spring loaded auto-
matic belt tensioner (Fig. 16). This belt tensioner will
be used on all belt configurations, such as with or
without power steering or air conditioning. For more
information, refer to Automatic Belt Tensioner, pro-
ceeding in this group.
(1) Attach a socket/wrench to pulley mounting bolt
of automatic tensioner (Fig. 16). The threads on the
pulley mounting bolt are left- hand.
(2) Relax the tension from the belt by rotating the
tensioner counterclockwise (as viewed from front)
(Fig. 16). When all belt tension has been relaxed,
remove belt from tensioner pulley first and other pul-
leys last.
INSTALLATION
CAUTION: When installing the accessory drive belt,
the belt must be routed correctly. If not, engine may
overheat due to water pump rotating in wrong
direction. Refer to (Fig. 17) (Fig. 18) for correct
engine belt routing. The correct belt with correct
length must be used.
CAUTION: If the pulley is to be removed from the
tensioner, its mounting bolt has left-hand threads.
Fig. 16 Belt Tensioner
1 - PULLEY BOLT
2 - IDLER PULLEY
3 - TENSIONER PULLEY
4 - TENSIONER
5 - TENSIONER MOUNTING BOLT
BR/BEACCESSORY DRIVE 7 - 29
DRIVE BELTS - 8.0L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
BELT BROKEN
(Note: Identify and correct problem
before new belt is installed)1. Incorrect belt tension 1. Replace Inspect/Replace
tensioner if necessary
2. Tensile member damaged during
belt installation2. Replace belt
3. Severe misalignment 3. Align pulley(s)
4. Bracket, pulley, or bearing failure 4. Replace defective component
and belt
NOISE (Objectional squeal, spueak,
or rumble is heard or felt while drive
belt is in operation)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Bearing noise 2. Locate and repair
3. Belt misalignment 3. Align belt/pulley(s)
4. Belt to pulley mismatch 4. Install correct belt
5. Driven component induced
vibration5. Locate defective driven
component and repair
TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)1. Tension sheeting contacting
stationary object1. Correct rubbing condition
2. Excessive heat causing woven
fabric to age2. Replace belt
3. Tension sheeting splice has
fractured3. Replace belt
CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Belt contacting stationary object 2. Replace belt
3. Pulley(s) out of tolerance 3. Replace pulley
4. Insufficient adhesion between
tensile member and rubber matrix4. Replace belt
REMOVAL
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner. Refer to Automatic Belt
Tensioner in this group.
NOTE: The belt routing schematics are published
from the latest information available at the time of
publication. If anything differs between these sche-
matics and the Belt Routing Label, use the sche-
matics on Belt Routing Label.This label is located in
the engine compartment.
Drive belts on diesel engines are equipped with a
spring loaded automatic belt tensioner (Fig. 20).
(Fig. 20) displays the tensioner for vehicles
without air conditioning.
This belt tensioner will be used on all belt configura-
tions, such as with or without air conditioning. For
more information, (Refer to 7 - COOLING/ACCESSORY
DRIVE/BELT TENSIONERS - DESCRIPTION).
(1) A 3/8 inch square hole is provided in the auto-
matic belt tensioner (Fig. 20). Attach a 3/8 inch
drive-long handle ratchet to this hole.
(2) Rotate ratchet and tensioner assembly counter-
clockwise (as viewed from front) until tension has
been relieved from belt.
(3) Remove belt from water pump pulley first.
(4) Remove belt from vehicle.
INSTALLATION
CAUTION: When installing the accessory drive belt,
the belt must be routed correctly. If not, engine may
overheat due to water pump rotating in wrong
direction. Refer to (Fig. 21) (Fig. 22) for correct
engine belt routing. The correct belt with correct
length must be used.
(1) Position drive belt over all pulleysexcept
water pump pulley.
(2) Attach a 3/8 inch ratchet to tensioner.
7 - 32 ACCESSORY DRIVEBR/BE
DRIVE BELTS - 5.9L DIESEL (Continued)

CAUTION: When installing the serpentine accessory
drive belt, the belt must be routed correctly. If not,
engine may overheat due to water pump rotating in
wrong direction. Refer to (Fig. 21) for correct 3.9L,
5.2L and 5.9L engine belt routing. The correct belt
with correct length must be used.
(7) Air Conditioned vehicles; Install generator.
Tighten bolts to 41 N´m (30 ft. lbs.).
(8) Install support bracket (generator mounting
bracket-to-intake manifold) (Fig. 16). Tighten bolts to
54 N´m (40 ft. lbs.) torque.
(9) Install accessory drive belt (Fig. 17)(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(10) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Connect battery negative cable.
(12) Start and warm the engine. Check for leaks.
Fig. 19 ThermostatÐ5.9L Engines
1 - THERMOSTAT HOUSING
2 - GASKET
3 - INTAKE MANIFOLD
4 - THERMOSTAT
5 - MACHINED GROOVE
Fig. 20 Thermostat PositionÐ5.9L Engines
Fig. 21 Belt RoutingÐ5.9L Engines
1 - IDLER PULLEY
2 - GENERATOR PULLEY
3 - A/C COMPRESSOR PULLEY
4 - IF W/OUT A/C
5 - POWER STEERING PUMP PULLEY
6 - WATER PUMP PULLEY
7 - CRANKSHAFT PULLEY
8 - AUTOMATIC TENSIONER
7 - 50 ENGINEBR/BE
ENGINE COOLANT THERMOSTAT - 5.9L (Continued)

(10)5.9L HDC-Gas:Install automatic belt ten-
sioner assembly to mounting bracket. A dowel pin is
located on back of tensioner (Fig. 71). Align this to
dowel hole (Fig. 72) in tensioner mounting bracket.
Tighten bolt to 41 N´m (30 ft. lbs.) torque.(11) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
CAUTION: When installing the serpentine accessory
drive belt, the belt must be routed correctly. If not,
the engine may overheat due to the water pump
rotating in the wrong direction (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION). The correct belt with the correct length must
be used.
(12) Install air cleaner assembly.
(13) Install upper radiator hose to radiator.
(14) Connect throttle cable to clip at radiator fan
shroud.
(15) Connect wiring harness to A/C compressor.
(16) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(17) Start and warm the engine. Check for leaks.
INSTALLATION - WATER PUMP BYPASS HOSE
WITHOUT AIR CONDITIONING
(1) Position bypass hose clamps to the center of
hose.
(2) Install bypass hose to engine.
(3) Secure both hose clamps.
(4) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(5) Start and warm the engine. Check for leaks.
Fig. 71 Tensioner Dowel Pin - 5.9L HDC-Gas Engine
1 - BELT TENSIONER
2 - DOWEL PIN
Fig. 72 Tensioner Mounting
1 - DOWEL PIN HOLE
2 - TENSIONER MOUNTING BRACKET
BR/BEENGINE 7 - 77
WATER PUMP INLET TUBE - 5.9L (Continued)

Three notches on the outer circumference of the cap
nut are engaged by matching projections of an
antenna nut wrench (Special Tool C-4816) to facili-
tate the removal and installation of this special fas-
tener. Proper tightening of the antenna cap nut is
critical to ensuring proper grounding of the antenna
body to the fender sheet metal, which is necessary
for clear radio signal reception.
A short length of coaxial cable serves as the pri-
mary antenna cable. The center conductor of the
cable is connected to the antenna mast receptacle.
The outer wire mesh of the cable is connected to and
grounded through the antenna body. One end of the
primary antenna cable is securely crimped to the
lower end of the antenna body, while the opposite
end features a simple push/pull-type male coaxial
cable connector that serves as the in-line connector to
the instrument panel (secondary) antenna coaxial
cable. The primary coaxial cable includes a grommet
that seals the cable to an entry hole in the right cowl
side outer panel where the cable passes into the pas-
senger compartment of the vehicle. The secondary
antenna cable has a push/pull-type male coaxial
cable connector on the radio end, and a push/pull-
type female coaxial cable connector on the opposite
end, which serves as the in-line connector to the pri-
mary antenna cable. In the passenger compartment
the primary cable is routed to the lower right side of
the instrument panel, where it is connected to the
secondary instrument panel antenna cable. The
instrument panel antenna cable is routed near the
instrument panel wire harness through the instru-
ment panel to the radio and is secured to the instru-
ment panel structural support with small metal
push-on retainers. This two-piece antenna cable
arrangement allows the instrument panel or the
antenna body and cable to be removed or installed
without disturbing the radio.
DIAGNOSIS AND TESTING - ANTENNA
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
The following four tests are used to diagnose the
antenna with an ohmmeter:
²Test 1- Mast to ground test
²Test 2- Tip-of-mast to tip-of-conductor test
²Test 3- Body ground to battery ground test
²Test 4- Body ground to coaxial shield test.The ohmmeter test lead connections for each test
are shown in Antenna Tests (Fig. 1).
NOTE: This model has a two-piece antenna coaxial
cable. Tests 2 and 4 must be conducted in two
steps to isolate a coaxial cable problem; from the
coaxial cable connection under the right end of the
instrument panel near the right cowl side inner
panel to the antenna base, and then from the coax-
ial cable connection to the radio receiver chassis
connection.
TEST 1
Test 1 determines if the antenna mast is insulated
from the base. Proceed as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector from the radio receiver chassis.
(2) Connect one ohmmeter test lead to the tip of
the antenna mast. Connect the other test lead to the
antenna base. Check for continuity.
(3) There should be no continuity. If continuity is
found, replace the faulty or damaged antenna base
and cable assembly.
TEST 2
Test 2 checks the antenna for an open circuit as
follows:
(1) Disconnect the antenna coaxial cable connector
from the radio receiver chassis.
(2) Connect one ohmmeter test lead to the tip of
the antenna mast. Connect the other test lead to the
center pin of the antenna coaxial cable connector.
(3) Continuity should exist (the ohmmeter should
only register a fraction of an ohm). High or infinite
resistance indicates damage to the base and cable
Fig. 1 Antenna Tests
BR/BEAUDIO 8A - 5
ANTENNA BODY & CABLE (Continued)

assembly. Replace the faulty or damaged antenna
base and cable, if required.
TEST 3
Test 3 checks the condition of the vehicle body
ground connection. This test should be performed
with the battery positive cable removed from the bat-
tery. Disconnect both battery cables, the negative
cable first. Reconnect the battery negative cable and
perform the test as follows:
(1) Connect one ohmmeter test lead to the vehicle
fender. Connect the other test lead to the battery
negative terminal post.
(2) The resistance should be less than one ohm.
(3) If the resistance is more than one ohm, check
the braided ground strap(s) connected to the engine
and the vehicle body for being loose, corroded, or
damaged. Repair the ground strap connections, if
required.
TEST 4
Test 4 checks the condition of the ground between
the antenna base and the vehicle body as follows:
(1) Connect one ohmmeter test lead to the vehicle
fender. Connect the other test lead to the outer crimp
on the antenna coaxial cable connector.
(2) The resistance should be less then one ohm.
(3) If the resistance is more then one ohm, clean
and/or tighten the antenna base to fender mounting
hardware.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
disengage the coaxial cable connector from the
retainer clip located on the bottom of the heater-A/C
housing (Fig. 2).
(3) Remove the foam tape to access the coaxial
cable connector. Disconnect the connector by pulling
it apart while twisting the metal connector halves.
Do not pull on the cable.
(4) Securely tie a suitable length of cord or twine
to the antenna half of the coaxial cable connector.
This cord will be used to pull or ªfishº the cable back
into position during installation.
(5) Reach above the Powertrain Control Module
(PCM) on the right side of the dash panel in the
engine compartment to disengage the antenna coax-
ial cable grommet from the hole in the dash panel
(Fig. 3).
(6) Pull the antenna coaxial cable out of the pas-
senger compartment and into the engine compart-
ment through the hole in the dash panel.(7) Raise the sleeve on the antenna mast far
enough to access and unscrew the antenna mast from
the antenna body (Fig. 4).
(8) Remove the antenna cap nut using an antenna
nut wrench (Special Tool C-4816) (Fig. 5).
(9) Remove the antenna adapter from the top of
the fender.
(10) Lower the antenna body and cable assembly
through the top of the fender.
(11) Pull the antenna body and cable out through
the opening between the right cowl side outer panel
and the top of the fender, while feeding the antenna
coaxial cable out of the engine compartment through
the hole in the right cowl side reinforcement.
(12) Untie the cord or twine from the antenna
body and cable coaxial cable connector, leaving the
cord or twine in the place of the cable through the
vehicle.
(13) Remove the antenna body and cable from the
vehicle.
INSTALLATION
(1) Tie the end of the cord or twine that was used
during instrument panel antenna cable removal
securely to the connector on the end of the antenna
cable being installed into the instrument panel. This
cord will be used to pull or ªfishº the cable back into
position.
Fig. 2 Antenna Coaxial Cable Connector
1 - RETAINER CLIP
2 - TO RADIO
3 - TO ANTENNA
4 - FOAM TAPE
8A - 6 AUDIOBR/BE
ANTENNA BODY & CABLE (Continued)

(4) Remove the two screws that secure the filter,
choke, and speaker relay mounting bracket to the
instrument panel center brace.
(5) Remove the filter, choke, and speaker relay
unit from under the instrument panel.
INSTALLATION
(1) Position the filter, choke, and speaker relay
unit under the instrument panel.
(2) Install and tighten the two screws that secure
the filter, choke, and speaker relay mounting bracket
to the instrument panel center brace. Tighten the
screws to 2.7 N´m (24 in. lbs.).
(3) Reconnect the instrument panel wire harness
connector to the filter, choke and speaker relay wire
harness connector.
(4) Reconnect the battery negative cable.
INSTRUMENT PANEL
ANTENNA CABLE
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
disengage the coaxial cable connector from the
retainer clip located on the bottom of the heater-A/C
housing.
(3) Remove the foam tape to access the coaxial
cable connector. Disconnect the connector by pulling
it apart while twisting the metal connector halves.
Do not pull on the cable.
(4) Securely tie a suitable length of cord or twine
to the instrument panel half of the antenna coaxial
cable connector. This cord will be used to pull or
ªfishº the cable back into position during installation.
(5) Roll down the glove box from the instrument
panel. Refer to Body, Instrument Panel for the proce-
dures.
(6) Reach through the glove box opening to disen-
gage the antenna cable from the retainer clips on the
back of the instrument panel (Fig. 7).
(7) Remove the radio receiver from the instrument
panel. Refer to Audio, Radio for the procedures.
(8) Pull the antenna cable out through the radio
receiver opening in the instrument panel.
(9) Untie the cord or twine from the instrument
panel antenna cable connector, leaving the cord or
twine in place of the cable in the instrument panel.
(10) Remove the antenna cable from the instru-
ment panel.
INSTALLATION
(1) Tie the end of the cord or twine that was used
during instrument panel antenna cable removal
securely to the connector on the end of the antenna
cable being installed into the instrument panel. This
cord will be used to pull or ªfishº the cable back into
position.
(2) Using the cord or twine, pull the antenna cable
through the radio receiver opening from under the
instrument panel.
(3) Install the radio receiver onto the instrument
panel. Refer to Audio, Radio for the procedures.
(4) Reach through the glove box opening to engage
the antenna cable with the retainer clips on the back
of the instrument panel.
(5) Install the glove box onto the instrument panel.
Refer to Body, Instrument Panel for the procedures.
(6) Untie the cord or twine from the instrument
panel antenna cable connector.
(7) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
reconnect the two halves of the radio antenna coaxial
cable connector. Wrap the connection with a piece of
foam tape.
(8) Engage the coaxial cable connector with the
retainer clip located on the bottom of the heater-A/C
housing.
(9) Reconnect the battery negative cable.
Fig. 7 ANTENNA CABLE ROUTING
1 - RETAINER CLIPS
2 - TO RADIO
3 - TO ANTENNA
BR/BEAUDIO 8A - 9
RADIO CHOKE RELAY (Continued)

BUS BIAS AND TERMINATION
The voltage network used by the CCD data bus to
transmit messages requires both bias and termina-
tion. At least one electronic control module on the
data bus must provide a voltage source for the CCD
data bus network known as bus bias, and there must
be at least one bus termination point for the data bus
circuit to be complete. However, while bias and ter-
mination are both required for data bus operation,
they both do not have to be within the same elec-
tronic control module. The CCD data bus is biased to
approximately 2.5 volts. With each of the electronic
control modules wired in parallel to the data bus, all
modules utilize the same bus bias. Therefore, based
upon vehicle options, the data bus can accommodate
two or twenty electronic control modules without
affecting bus voltage.
The power supplied to the data bus is known as
bus biasing. Bus bias is provided through a series cir-
cuit. To properly bias the data bus circuits, a 5 volt
supply is provided through a 13 kilohm resistor to
the Bus (±) circuit (Fig. 6). Voltage from the Bus (±)
circuit flows through a 120 ohm termination resistor
to the Bus (+) circuit. The Bus (+) circuit is grounded
through another 13 kilohm resistor. While at least
one termination resistor is required for the system to
operate, most DaimlerChrysler systems use two. The
second termination resistor serves as a backup (Fig.
7). The termination resistor provides a path for the
bus bias voltage. Without a termination point, volt-
age biasing would not occur. Voltage would go to 5
volts on one bus wire and 0 volts on the other bus
wire.The voltage drop through the termination resistor
creates 2.51 volts on Bus (±), and 2.49 volts on Bus
(+). The voltage difference between the two circuits is
0.02 volts. When the data bus voltage differential is a
steady 0.02 volts, the CCD system is considered
ªidle.º When no input is received from any module
and the ignition switch is in the Off position for a
pre-programmed length of time, the bus data
becomes inactive or enters the ºsleep mode.º Elec-
tronic control modules that provide bus bias can be
programmed to ºwake upº the data bus and become
active upon receiving any predetermined input or
when the ignition switch is turned to the On posi-
tion.
BUS MESSAGING
The electronic control modules used in the CCD
data bus system contain microprocessors. Digital sig-
nals are the means by which microprocessors operate
internally and communicate messages to other micro-
processors. Digital signals are limited to two states,
voltage high or voltage low, corresponding to either a
one or a zero. Unlike conventional binary code, the
CCD data bus systems translate a small voltage dif-
ference as a one (1), and a larger voltage difference
as a zero (0). The use of the 0 and 1 is referred to as
binary coding. Each binary number is called a bit,
and eight bits make up a byte. For example:
01011101 represents a message. The controllers in
the multiplex system are able to send thousands of
these bytes strung together to communicate a variety
of messages. Through the use of binary data trans-
mission, all electronic control modules on the data
bus can communicate with each other.
The microprocessors in the CCD data bus system
translate the binary messages into Hexadecimal
Code (or Hex Code). Hex code is the means by which
microprocessors communicate and interpret mes-
sages. When fault codes are received by the DRBIIIt
scan tool, they are translated into text for display on
the DRBIIItscreen. Although not displayed by the
DRBIIItfor Body Systems, hex codes are shown by
the DRBIIItfor Engine System faults.
When the microprocessor signals the transceiver in
the CCD chip to broadcast a message, the transceiver
turns the current drivers On and Off, which cycles
the voltage on the CCD data bus circuits to corre-
spond to the message. At idle, the CCD system rec-
ognizes the 0.02 voltage differential as a binary bit 1.
When the current drivers are actuated, the voltage
differential from idle must increase by 0.02 volt for
the CCD system to recognize a binary bit 0 (Fig. 8).
The nominal voltage differential for a 0 bit is 0.100
volts. However, data bus voltage differentials can
range anywhere between 0.02 and 0.120 volt.
Fig. 6 Bus Biasing
8E - 8 ELECTRONIC CONTROL MODULESBR/BE
COMMUNICATION (Continued)