radio DODGE RAM 1500 1998 2.G Workshop Manual
[x] Cancel search | Manufacturer: DODGE, Model Year: 1998, Model line: RAM 1500, Model: DODGE RAM 1500 1998 2.GPages: 2627
Page 386 of 2627
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
Page 387 of 2627
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)
Page 388 of 2627
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/VIDEO 8A - 3
AUDIO (Continued)
Page 389 of 2627
(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)
Page 390 of 2627
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)
Page 391 of 2627
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)
Page 392 of 2627
(5) Connect battery negative cable.
INSTRUMENT PANEL
ANTENNA CABLE
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the glove box (Refer to 23 - BODY/IN-
STRUMENT PANEL/GLOVE BOX - REMOVAL).
(3) Remove the instrument panel center bezel
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL CENTER BEZEL - REMOVAL).
(4) Remove the instrument panel lower right cen-
ter bezel (Refer to 23 - BODY/INSTRUMENT PAN-
EL/IP LOWER RIGHT CENTER BEZEL -
REMOVAL).
(5) Remove the radio (Refer to 8 - ELECTRICAL/
AUDIO/RADIO - REMOVAL).
CAUTION: Pulling the antenna cable straight out of
the radio without pulling on the locking antenna
connector could damage the cable or radio.
(6) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
6)
(7) Remove antenna cable from instrument panel
by pulling on retaining fasteners (Fig. 7).
INSTALLATION
(1) Install antenna cable to instrument panel by
pressing retaining fasteners into position.
(2) Connect instrument panel antenna cable to
antenna body and cable.
(3) Install radio (Refer to 8 - ELECTRICAL/AU-
DIO/RADIO - INSTALLATION).
(4) Install the instrument panel lower right center
bezel (Refer to 23 - BODY/INSTRUMENT PANEL/IP
LOWER RIGHT CENTER BEZEL - INSTALLA-
TION).
(5) Install the instrument panel center bezel (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - INSTALLATION).
Fig. 5 NAVIGATION ANTENNA ROUTING
1 - NAVIGATION ANTENNA
2 - INSTRUMENT PANEL
3 - RADIO (REAR VIEW)
Fig. 6 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
Fig. 7 INSTRUMENT PANEL ANTENNA CABLE
1 - INSTRUMENT PANEL ANTENNA CABLE
2 - ANTENNA BODY AND CABLE
DRAUDIO/VIDEO 8A - 7
ANTENNA - NAVIGATION (Continued)
Page 393 of 2627
(6) Install the glove box (Refer to 23 - BODY/IN-
STRUMENT PANEL/GLOVE BOX - INSTALLA-
TION).
(7) Connect the battery negative cable.
RADIO
DESCRIPTION
Available radio receivers for this vehicle include:
²AM/FM/cassette with CD changer control fea-
ture (RBB sales code)
²AM/FM/cassette/CD/ with CD changer control
feature (RAZ sales code)
²AM/FM/CD with CD changer control feature
(RBK sales code)
²AM/FM/cassette/CD with CD changer control
(RBY sales code)
²AM/FM/CD with GPS navigation (RB4 sales
code)
²AM/FM/cassette/CD (RBY sales code) - export
only
All factory-installed radio receivers can communi-
cate on the Programmable Communications Interface
(PCI) data bus network. All factory-installed receiv-
ers are stereo Electronically Tuned Radios (ETR) and
include an electronic digital clock function.
OPERATION
The radio receiver operates on ignition switched
battery current that is available only when the igni-
tion switch is in the On or Accessory positions. The
electronic digital clock function of the radio operates
on fused battery current supplied through the IOD
fuse, regardless of the ignition switch position.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove center instrument panel bezel (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - REMOVAL).
(3) Remove radio mounting screws (Fig. 8).
(4) Disconnect electrical harness connector.
CAUTION: Pulling the antenna cable straight out of
the radio without pulling on the locking antenna
connector could damage the cable or radio.
(5) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
9)
INSTALLATION
(1) Install antenna cable to radio.
(2) Connect electrical harness connector to radio.
(3) Install radio to instrument panel.
(4) Install instrument panel center bezel (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - INSTALLATION).
(5) Connect battery negative cable.
Fig. 8 RADIO
Fig. 9 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
8A - 8 AUDIO/VIDEODR
INSTRUMENT PANEL ANTENNA CABLE (Continued)
Page 394 of 2627
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
Page 395 of 2627
ENGINE TO HEAT SHIELD - 3.7L ENGINE
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the attaching bolts from the cylinder
heads (Fig. 11).
(3) Remove nut from heat shield and remove strap
(Fig. 12).
ENGINE TO HEAT SHIELD - 4.7L AND 5.7L ENGINE
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the attaching bolts from the cylinder
heads (Fig. 13).
(3) Remove nut from heat shield and remove strap
(Fig. 12).
INSTALLATION
BED TO CAB
(1) Install the ground strap and retaining bolts.
Tighten to 5 N´m (45 in. lbs.).
(2) Connect the battery negative cable.
ENGINE TO HEAT SHIELD
(1) Install the retaining nut and ground strap to
the plenum. Tighten to 8 N´m (70 in. lbs.).
(2) Install the retaining bolt and ground strap to
the engine cylinder heads. Tighten to 12 N´m (106 in.
lbs.).
(3) Connect the battery negative cable.
REMOTE SWITCHES
DESCRIPTION
A remote radio control switch option is available on
some models. Two rocker-type switches are mounted
on the back (instrument panel side) of the steering
wheel spokes (Fig. 14). The switch on the left spoke
is the seek switch and has seek up, seek down, and
preset station advance functions. The switch on the
right spoke is the volume control switch and has vol-
ume up, and volume down functions. The switch on
the right spoke also includes a ªmodeº control that
allows the driver to sequentially select AM radio, FM
radio, cassette player, CD player or CD changer (if
equipped).
Fig. 11 ENGINE GROUND STRAP - 3.7L
1 - GROUND STRAP
2 - MOUNTING BOLTS
Fig. 12 GROUND STRAP TO HEAT SHIELD
1 - STUD
2 - GROUND STRAP
3 - NUT
Fig. 13 ENGINE GROUND STRAP - 4.7L AND 5.7L
1 - GROUND STRAP
2 - MOUNTING BOLTS
8A - 10 AUDIO/VIDEODR
RADIO NOISE SUPPRESSION GROUND STRAP (Continued)