One DODGE RAM 1500 1998 2.G Workshop Manual

REMOVAL
NOTE:
The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
The water pump on all gas powered engines is
bolted directly to the engine timing chain case/
cover.
On the 8.0L V-10 engine, a rubber o-ring (instead of
a gasket) is used as a seal between the water pump
and timing chain case/cover.
If water pump is replaced because of bearing/shaft
damage or leaking shaft seal, the mechanical cooling
fan assembly should also be inspected. Inspect for
fatigue cracks, loose blades or loose rivets that could
have resulted from excessive vibration. Replace fan if
any of these conditions are found. Also check condi-
tion of the thermal viscous fan drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - DIAGNOSIS AND TESTING).
(1) Disconnect negative battery cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
(3) Remove windshield washer reservoir tank from
radiator fan shroud.
(4) Remove the four fan shroud mounting bolts at
the radiator (Fig. 51). Do not attempt to remove
shroud from vehicle at this time.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL NUMBER
6094. ALWAYS WEAR SAFETY GLASSES WHEN
SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(5) Remove radiator upper hose at radiator.
(6) The thermal viscous fan drive is threaded on to
the water pump hub shaft (Fig. 53). Remove the fan/
fan drive assembly from water pump by turning the
mounting nut counterclockwise (as viewed from
front). Threads on the fan drive areRIGHT-HAND.
A 36 MM fan wrench can be used with Tool 6958
Spanner Wrench and Adapter Pins 8346 (Fig. 52) to
prevent the pulley from rotating.
(7) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 53) from the thermal control
fan drive.
(8) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
After removing fan blade/fan drive assembly,do
notplace the thermal viscous fan drive in the hori-
zontal position. If stored horizontally, the silicone
Fig. 51 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
Fig. 52 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 64 ENGINEDR
WATER PUMP - 8.0L (Continued)

fluid in the viscous drive could drain into its bearing
assembly and contaminate the bearing lubricant.
(9) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 54).
(10) Remove the radiator lower hose at water
pump.(11) Remove heater hose at water pump fitting.
(12) Remove the seven water pump mounting bolts
(Fig. 55).
(13) Loosen the clamp at the water pump end of
bypass hose. Slip the bypass hose from the water
pump while removing pump from vehicle. Do not
remove the clamp from the bypass hose.
(14) Discard the water pump-to-timing chain/case
cover o-ring seal (Fig. 56).
Fig. 53 Water Pump Location - Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
Fig. 54 Belt Tensioner - 8.0L V-10 Engines
1 - PULLEY BOLT
2 - IDLER PULLEY
3 - TENSIONER PULLEY
4 - TENSIONER
5 - TENSIONER MOUNTING BOLT
Fig. 55 Water Pump Bolts - 8.0L V-10 - Typical
1 - WATER PUMP MOUNTING BOLTS (7)
Fig. 56 Water Pump O-Ring Seal - 8.0L V-10
1 - WATER PUMP
2 - O-RING SEAL
DRENGINE 7 - 65
WATER PUMP - 8.0L (Continued)

DISASSEMBLY - 5.9L DIESEL 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. 7).
(3) Remove the end plug, thermostat and spring
from transmission oil cooler (Fig. 7).
ASSEMBLY - 5.9L DIESEL 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
INSTALLATION - AIR TO OIL COOLER
(1) Carefully position the oil cooler assembly to the
vehicle.
(2) Install two nuts and one bolt. Tighten to 11
N´m (95 in. lbs.) torque.
(3) Connect the quick-connect fittings to the trans-
mission cooler lines.
(4) Install Charge Air Cooler (Refer to 11 -
EXHAUST SYSTEM/TURBOCHARGER SYSTEM/
CHARGE AIR COOLER AND PLUMBING -
INSTALLATION).
(5) Start the engine and check all fittings for
leaks.
(6) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
INSTALLATION - WATER-TO-AIR COOLER
(1) Position oil cooler on cylinder block.
(2) Install lower mounting bolt to cooler at the cyl-
inder block. Torque bolt to 77 N´m (57 ft. lbs.)
(3) Install upper mounting bolt at the cylinder
block. Torque bolt to 24 N´m (19 ft. lbs.)
(4) Install cooler bracket to transmission adapter
bolt. Tighten to 24 N´m (18 ft. lbs.).
(5) Connect transmission oil lines to cooler.
(6) Connect coolant hoses to cooler.
(7) Install starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - INSTALLA-
TION).
(8) Connect battery negative cables.
(9) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(10) Check transmission oil level and fill as neces-
sary (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
Fig. 7 Transmission Oil Cooler Thermostat
Removal/Installation
1 - THERMOSTAT HOUSING
2 - SPRING
3 - END PLUG
4 - SNAP RING
5 - THERMOSTAT
7 - 70 TRANSMISSIONDR
TRANS COOLER - 5.9L DIESEL (Continued)

AUDIO/VIDEO
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
ANTENNA - NAVIGATION
REMOVAL.............................6
INSTALLATION..........................6
INSTRUMENT PANEL ANTENNA CABLE
REMOVAL.............................7
INSTALLATION..........................7
RADIO
DESCRIPTION..........................8OPERATION............................8
REMOVAL.............................8
INSTALLATION..........................8
RADIO NOISE SUPPRESSION GROUND STRAP
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................9
INSTALLATION.........................10
REMOTE SWITCHES
DESCRIPTION.........................10
OPERATION...........................11
DIAGNOSIS AND TESTING - REMOTE
SWITCHES..........................11
REMOVAL.............................12
INSTALLATION.........................12
SPEAKER
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - SPEAKER......13
REMOVAL.............................14
INSTALLATION.........................15
AUDIO
DESCRIPTION
Several combinations of radio receivers and
speaker systems are offered. The audio system uses
an ignition switched source of battery current so that
the system will only operate when the ignition switch
is in the RUN or ACCESSORY positions.
A optional navigation radio (RB4) is available on
this vehicle. With this system, the operator has the
option of choosing a street address, point of interest,
trip itinerary and other features outlined in the oper-
ator's manual.
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)
²SpeakersCertain 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 tool
and the proper Diagnostic Procedures manual are
recommended.
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.
DRAUDIO/VIDEO 8A - 1

The optional navigation radio system receives GPS
signals from up to eight satellites to display the posi-
tion and direction of the vehicle. Map information is
supplied through a DVD-ROM. An electronic gyro-
sensor and the vehicle's speed sensor enable the sys-
tem to display the present vehicle position even in
locations where GPS signals may be blocked.
When a destination is selected, the navigation sys-
tem uses information from the map to quickly calcu-
late a route. As the vehicle is driven along the chosen
route, the operator is guided with pictorial displays
and voice prompts. For complete operating instruc-
tions, refer to the manual included with the vehicle.
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
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.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.
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 AUDIO/VIDEODR
AUDIO (Continued)

(3) Remove instrument panel center bezel (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - REMOVAL).
(4) Remove instrument panel lower right center
bezel (Refer to 23 - BODY/INSTRUMENT PANEL/IP
LOWER RIGHT CENTER BEZEL - REMOVAL).
(5) Disconnect electrical harness connector from
amplifier (Fig. 1).
(6) Remove mounting bolts.
INSTALLATION
(1) Connect electrical harness connector and
install amplifier.
(2) Install mounting bolts. Tighten to 10 N´m (90
in. lbs.).
(3) Install instrument panel lower right center
bezel (Refer to 23 - BODY/INSTRUMENT PANEL/IP
LOWER RIGHT CENTER BEZEL - INSTALLA-
TION).
(4) Install instrument panel center bezel (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - INSTALLATION).
(5) Install glove box (Refer to 23 - BODY/INSTRU-
MENT PANEL/GLOVE BOX - INSTALLATION).
(6) Connect battery negative cable.
ANTENNA BODY & CABLE
DESCRIPTION
The antenna body and cable is secured below the
fender panel by the antenna cap nut through a
mounting hole in the right front fender. The primary
coaxial antenna cable is then routed beneath the
fender sheet metal and through a entry hole in theright cowl side panel into the interior of the vehicle.
Inside the vehicle, the primary coaxial cable is con-
nected to a secondary instrument panel antenna
coaxial cable with an in-line connector that is located
behind the right kick panel. The secondary coaxial
cable is then routed behind the instrument panel to
the back of the radio.
OPERATION
The antenna body and cable connects the antenna
mast to the radio. The radio antenna is an electro-
magnetic circuit component used to capture radio fre-
quency signals that are broadcast by local
commercial radio stations in both the Amplitude
Modulating (AM) and Frequency Modulating (FM)
frequency ranges. These electromagnetic radio fre-
quency signals induce small electrical modulations
into the antenna as they move past the mast. The
antenna body transfers the weak electromagnetic
radio waves induced into the rigid antenna mast into
the center conductor of the flexible primary antenna
coaxial cable. The braided outer shield of the
antenna coaxial cable is grounded through both the
antenna body and the radio chassis, effectively
shielding the radio waves as they are conducted to
the radio. The radio then tunes and amplifies the
weak radio signals into stronger electrical signals in
order to operate the audio system speakers.
DIAGNOSIS AND TESTING - ANTENNA BODY
AND CABLE
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 antenna coaxial cable
shield test.
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.
The ohmmeter test lead connections for each test
are shown in the illustration (Fig. 2).
Fig. 1 AMPLIFIER MOUNTING
1 - INSTRUMENT PANEL
2 - AMPLIFIER
3 - MOUNTING BOLTS
4 - ELECTRICAL CONNECTOR
8A - 4 AUDIO/VIDEODR
AMPLIFIER (Continued)

NOTE: This model has a two-piece antenna coaxial
cable. Tests 2 and 4 must be conducted in two
steps to isolate an antenna cable problem. First,
test the primary antenna cable (integral to the
antenna body and cable) from the coaxial cable
connector behind the right side kick panel to the
antenna body. Then, test the secondary antenna
cable (instrument panel antenna cable) from the
coaxial cable connector behind the right side kick
panel to the coaxial cable connector at the radio.
TEST 1
Test 1 determines if the antenna mast is insulated
from ground. Proceed as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector behind the right side kick panel.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast. Touch the other test lead to known
ground. Check the ohmmeter reading for continuity.
(3) There should be no continuity. If OK, go to Test
2. If not OK, replace the faulty antenna body and
cable.
TEST 2
Test 2 checks the antenna conductor components
for an open circuit. This test should be performed
first on the entire antenna circuit, from the antenna
mast to the center conductor of the coaxial cable con-
nector at the radio. If an open circuit is detected,
each of the three antenna conductor components
(antenna mast, antenna body and cable, instrument
panel antenna cable) should be isolated and tested
individually to locate the exact component that is the
source of the open circuit. To begin this test, proceed
as follows:(1) Disconnect the instrument panel antenna cable
coaxial connector from the back of the radio.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast. Touch the other test lead to the center
conductor pin of the instrument panel antenna cable
coaxial connector for the radio. Check the ohmmeter
reading for continuity.
(3) There should be continuity. The ohmmeter
should register only a fraction of an ohm resistance.
High or infinite resistance indicates a damaged or
open antenna conductor. If OK, go to Test 3. If not
OK, isolate and test each of the individual antenna
conductor components. Replace only the faulty
antenna conductor component.
TEST 3
Test 3 checks the condition of the vehicle body
ground connection. To begin this test, proceed as fol-
lows:
(1) This test must be performed with the battery
positive cable disconnected from the battery. Discon-
nect and isolate both battery cables, negative cable
first.
(2) Reconnect the battery negative cable.
(3) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the battery negative terminal post. Check
the ohmmeter reading for continuity.
(4) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the battery negative
terminal and the vehicle body. If OK, go to Test 4. If
not OK, check the battery negative cable connection
to the vehicle body and the radio noise suppression
ground strap connections to the engine and the vehi-
cle body for being loose or corroded. Clean or tighten
these connections as required.
TEST 4
Test 4 checks the condition of the connection
between the antenna coaxial cable shield and the
vehicle body ground as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector behind the right side kick panel.
(2) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the outer crimp on the antenna coaxial
cable connector. Check the ohmmeter reading for con-
tinuity.
(3) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the antenna body and
the vehicle body or between the antenna body and
the antenna coaxial cable shield. If not OK, clean the
Fig. 2 Antenna Tests - Typical
DRAUDIO/VIDEO 8A - 5
ANTENNA BODY & CABLE (Continued)

antenna body to fender mating surfaces and tighten
the antenna cap nut to specifications.
(4) Check the resistance again with an ohmmeter.
If the resistance is still more then one ohm, replace
the faulty antenna body and cable.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right side kick panel.
(3) Disconnect antenna body cable from instru-
ment panel 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 the cable back into
position during installation.
(5) Remove the antenna mast.
(6) Remove the antenna cap nut using an antenna
nut wrench (Special Tool C-4816) (Fig. 3).
(7) Remove the antenna adapter.
(8) With the right door open, pull the antenna
body assembly out through the opening between the
fender and body.
INSTALLATION
(1) Tie the cord that was used during the removal
procedure to the cable being installed.
(2) Using the cord, pull the antenna cable through
the hole in the door opening and seat grommet into
place.
(3) Connect the antenna body and cable to the
instrument panel cable.
(4) Install the right side kick panel.(5) Insert the antenna body through the hole in
the fender and install adapter.
(6) Install the antenna cap nut. Tighten to 7 N´m
(65 in. lbs.).
(7) Install the antenna mast.
(8) Connect the battery negative cable.
ANTENNA - NAVIGATION
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel top cover (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - REMOVAL).
(3) Remove the radio (Refer to 8 - ELECTRICAL/
AUDIO/RADIO - REMOVAL).
(4) Remove the antenna mounting fasteners (Fig.
4).
(5) Cut each end of the cable and leave remaining
portion in the instrument panel (Fig. 5).
INSTALLATION
(1) Position new antenna cable to wire harness.
Secure into place.
(2) Install antenna mounting fasteners.
(3) Install radio (Refer to 8 - ELECTRICAL/AU-
DIO/RADIO - INSTALLATION).
(4) Install instrument panel top cover (Refer to 23
- BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION).
Fig. 3 ANTENNA BODY AND CABLE
1 - NUT
2 - FENDER
3 - ANTENNA BODY AND CABLE
4 - ADAPTER
Fig. 4 NAVIGATION ANTENNA MOUNTING
8A - 6 AUDIO/VIDEODR
ANTENNA BODY & CABLE (Continued)

RADIO NOISE SUPPRESSION
GROUND STRAP
DESCRIPTION
Radio noise suppression devices are factory-in-
stalled standard equipment on this vehicle. Radio
Frequency Interference (RFI) and ElectroMagnetic
Interference (EMI) can be produced by any on-board
or external source of electromagnetic energy. These
electromagnetic energy sources can radiate electro-
magnetic signals through the air, or conduct them
through the vehicle electrical system.
When the audio system converts RFI or EMI to an
audible acoustic wave form, it is referred to as radio
noise. This undesirable radio noise is generally man-
ifested in the form of ªbuzzing,º ªhissing,º ªpopping,º
ªclicking,º ªcrackling,º and/or ªwhirringº sounds. In
most cases, RFI and EMI radio noise can be sup-
pressed using a combination of vehicle and compo-
nent grounding, filtering and shielding techniques.
This vehicle is equipped with factory-installed radio
noise suppression devices that were designed to min-
imize exposure to typical sources of RFI and EMI;
thereby, minimizing radio noise complaints.
Factory-installed radio noise suppression is accom-
plished primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical com-
ponents such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
²Engine-to-body ground strap- This length of
braided ground strap has an eyelet terminal connec-
tor crimped to each end. One end is secured to the
engine cylinder head(s). The other is secured to the
plenum at the exhaust heat shield forward/outer
attaching stud.
²Resistor-type spark plugs- This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center elec-
trode to help reduce the production of electromag-
netic radiation that can result in radio noise.
OPERATION
There are two common strategies that can be used
to suppress Radio Frequency Interference (RFI) and
ElectroMagnetic Interference (EMI) radio noise. The
first suppression strategy involves preventing the
production of RFI and EMI electromagnetic signals
at their sources. The second suppression strategy
involves preventing the reception of RFI and EMIelectromagnetic signals by the audio system compo-
nents.
The use of braided ground straps in key locations
is part of the RFI and EMI prevention strategy.
These ground straps ensure adequate ground paths,
particularly for high current components such as
many of those found in the starting, charging, igni-
tion, engine control and transmission control sys-
tems. An insufficient ground path for any of these
high current components may result in radio noise
caused by induced voltages created as the high cur-
rent seeks alternative ground paths through compo-
nents or circuits intended for use by, or in close
proximity to the audio system components or circuits.
Preventing the reception of RFI and EMI is accom-
plished by ensuring that the audio system compo-
nents are correctly installed in the vehicle. Loose,
corroded or improperly soldered wire harness connec-
tions, improperly routed wiring and inadequate audio
system component grounding can all contribute to
the reception of RFI and EMI. A properly grounded
antenna body and radio chassis, as well as a shielded
antenna coaxial cable with clean and tight connec-
tions will each help reduce the potential for reception
of RFI and EMI.
REMOVAL
BED TO CAB
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the attaching bolts and strap (Fig. 10).
Fig. 10 BED TO CAB GROUND STRAP
1 - BED
2 - CAB
3 - GROUND STRAP
4 - MOUNTING BOLTS
DRAUDIO/VIDEO 8A - 9

OPERATION
The six switches in the two remote radio switch
units are normally open, resistor multiplexed
momentary switches that are hard wired to the Inte-
grated Power Module (IPM) through the clockspring.
The IPM sends a five volt reference signal to both
switch units on one circuit, and senses the status of
all of the switches by reading the voltage drop on a
second circuit.
When the IPM senses an input (voltage drop) from
any one of the remote radio switches, it sends the
proper switch status messages on the Programmable
Communication Interface (PCI) data bus network to
the radio receiver. The electronic circuitry within the
radio receiver is programmed to respond to these
remote radio switch status messages by adjusting the
radio settings as requested. For diagnosis of the IPM
or the PCI data bus, the use of a DRB IIItscan tool
and the proper Diagnostic Procedures manual are
recommended.
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.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. 15)
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.
Fig. 14 Remote Radio Switch Operational View
1 - PRESET SEEK
2 - SEEK UP
3 - VOLUME UP
4 - MODE
5 - VOLUME DOWN
6 - SEEK DOWN
Fig. 15 Remote Radio Switches
1 - BLACK (LEFT) SWITCH
2 - WHITE (RIGHT) SWITCH
DRAUDIO/VIDEO 8A - 11
REMOTE SWITCHES (Continued)