Dodge Durango (DN). Manual — part 285

on the steering wheel through a hard wired circuit.
The CTM then sends the proper switch status mes-
sages to the radio receiver. The electronic circuitry
within the radio receiver responds to the switch sta-
tus messages it receives by adjusting the radio set-
tings as requested.

Refer to Central Timer Module in the Descrip-

tion and Operation section of Group 8E - Instrument
Panel Systems for more information on the high-line
CTM. Refer to Remote Radio Switch in the
Description and Operation section of this group for
more information on this component. In addition,
radio receivers connected to the CCD data bus have
several audio system functions that can be diagnosed
using a DRB scan tool. Refer to the proper Diagnostic
Procedures manual for more information on DRB
testing of the audio systems.

RADIO RECEIVER

DESCRIPTION

Available factory-installed radio receivers for this

model include an AM/FM/cassette (RAS sales code),
an AM/FM/cassette/5-band graphic equalizer with CD
changer control feature (RBN sales code), an AM/FM/
CD/3-band graphic equalizer (RBR sales code), or an
AM/FM/CD/cassette/3-band graphic equalizer (RAZ
sales code). The factory-installed RAZ sales code
radio receivers can also communicate on the Chrysler
Collision Detection (CCD) data bus network through
a separate two-way wire harness connector. All facto-
ry-installed receivers are stereo Electronically Tuned
Radios (ETR) and include an electronic digital clock
function.

These radio receivers can only be serviced by an

authorized radio repair station. See the latest War-
ranty Policies and Procedures manual for a current
listing of authorized radio repair stations.

IGNITION-OFF DRAW FUSE

All vehicles are equipped with an Ignition-Off

Draw (IOD) fuse that is removed when the vehicle is
shipped from the factory. This fuse feeds various
accessories that require battery current when the
ignition switch is in the Off position, including the
clock. The IOD fuse is removed to prevent battery
discharge during vehicle storage.

When removing or installing the IOD fuse, it is

important that the ignition switch be in the Off posi-
tion. Failure to place the ignition switch in the Off
position can cause the radio display to become scram-
bled when the IOD fuse is removed and replaced.
Removing and replacing the IOD fuse again, with the
ignition switch in the Off position, will correct the
scrambled display condition.

The IOD fuse should be checked if the radio or

clock displays are inoperative. The IOD fuse is
located in the junction block. Refer to the fuse layout
label on the back of the instrument panel fuse access
panel for IOD fuse identification and location.

OPERATION

The radio receiver operates on fused battery cur-

rent that is available only when the ignition switch is
in the On or Accessory positions. The electronic digi-
tal clock function of the radio operates on fused bat-
tery

current

supplied

through

the

IOD

fuse,

regardless of the ignition switch position.

For more information on the features, setting pro-

cedures, and control functions for each of the avail-
able factory-installed radio receivers, see the owner’s
manual in the vehicle glove box. For complete circuit
diagrams, refer to Audio System in the Contents of
Group 8W - Wiring Diagrams.

REMOTE RADIO SWITCH

DESCRIPTION

A remote radio switch option is available on models

equipped

with

the

AM/FM/CD/cassette/3-band

graphic equalizer (RAZ sales code) radio receiver and
the high-line Central Timer Module (CTM). Refer to
Central Timer Module in the Description and
Operation section of Group 8E - Instrument Panel
Systems for more information on this component.

Two rocker-type switches (Fig. 1) are mounted in

the sides of the rear (instrument panel side) steering
wheel trim cover. The switch on the left side is the
seek switch and has seek up, seek down, and preset
station advance functions. The switch on the right
side is the volume control switch and has volume up,
and volume down functions. The two switches are
retained in mounting holes located on each side of
the rear steering wheel trim cover by four latches
that are integral to the switches.

The remote radio switches share a common steer-

ing wheel wire harness with the vehicle speed control
switches. The steering wheel wire harness is con-
nected to the instrument panel wire harness through
the

clockspring.

Refer

to

Clockspring

in

the

Description and Operation section of Group 8M -
Passive Restraint Systems for more information on
this component.

OPERATION

The remote radio switches are resistor multiplexed

units that are hard wired to the high-line CTM
through the clockspring. The CTM monitors the sta-
tus of the remote radio switches and sends the
proper switch status messages on the Chrysler Colli-
sion Detection (CCD) data bus network to the radio

8F - 2

AUDIO SYSTEMS

DN

DESCRIPTION AND OPERATION (Continued)

receiver. The electronic circuitry within the radio is
programmed to respond to these remote radio switch
status messages by adjusting the radio settings as
requested.

For diagnosis of the CTM or the CCD data bus, the

use of a DRB scan tool and the proper Diagnostic
Procedures manual are recommended. For more
information on the features and control functions for
each of the remote radio switches, see the owner’s
manual in the vehicle glove box. For complete circuit
diagrams, refer to Audio System in the Contents of
Group 8W - Wiring Diagrams.

SPEAKER SYSTEM

DESCRIPTION

STANDARD

The standard equipment speaker system includes

speakers in four locations. One full-range 16.5 centi-
meter (6.5 inch) diameter speaker is located in each
front door. There is also one full-range 16.5 centime-
ter (6.5 inch) diameter speaker located in each rear
door.

PREMIUM

The optional premium speaker system features

eight Infinity model speakers in six locations. Each of
the standard speakers in the front doors is replaced
with Infinity model speakers, and an additional 6.9
centimeter

(2.75

inch)

diameter

Infinity

dome

tweeter is mounted high in the front door trim pan-

els. The standard speakers in the rear doors are each
replaced with an Infinity 16.5 centimeter (6.5 inch)
diameter coaxial unit. The premium speaker system
also includes an additional Infinity power amplifier.
The total available power of the premium speaker
system is about 100 watts.

OPERATION

STANDARD

Each of the four full-range speakers used in the

standard speaker system is driven by the amplifier
that is integral to the factory-installed radio receiver.
For complete circuit diagrams, refer to Audio Sys-
tem in the Contents of Group 8W - Wiring Diagrams.

PREMIUM

The eight Infinity speakers used in the premium

speaker system are all driven by the radio receiver
through an Infinity power amplifier. For complete cir-
cuit diagrams, refer to Audio System in the Con-
tents of Group 8W - Wiring Diagrams.

POWER AMPLIFIER

DESCRIPTION

Models

equipped

with

the

Infinity

premium

speaker package have a separate power amplifier
unit. This power amplifier is rated at 100 watts out-
put. The power amplifier unit is mounted to the right
cowl side inner panel under the passenger side end of
the instrument panel. The power amplifier unit can
be accessed for service by removing the trim from the
right cowl side inner panel.

The power amplifier unit should be checked if

there is no sound output noted from the speakers.
For diagnosis of the power amplifier, refer to
Speaker in the Diagnosis and Testing section of this
group. The power amplifier cannot be repaired or
adjusted and, if faulty or damaged, the unit must be
replaced.

OPERATION

The power amplifier receives fused battery current

from a fuse in the Junction Block (JB) at all times.
The internal circuitry of the power amplifier switches
the amplifier on based upon a fused 12 volt output
signal that is received from the radio receiver when-
ever the radio is turned on. The power amplifier
receives the sound signal inputs for four speaker
channels from the radio receiver, then sends the
amplified speaker outputs for each of those channels
to the eight speakers. For complete circuit diagrams,
refer to Audio System in the Contents of Group 8W
- Wiring Diagrams.

Fig. 1 Remote Radio Switches

1 – PRESET SEEK
2 – UP
3 – SEEK
4 – VOLUME
5 – DOWN

DN

AUDIO SYSTEMS

8F - 3

DESCRIPTION AND OPERATION (Continued)

ANTENNA

DESCRIPTION

All models use a black painted fixed-length stain-

less steel rod-type antenna mast, installed on the
right front fender of the vehicle. The antenna mast
has a spiral groove cut down its length to reduce
wind noise. The antenna mast is connected to the
center wire of the coaxial antenna cable, and is not
grounded to any part of the vehicle. To eliminate
static, the antenna base must have a good ground.
The coaxial antenna cable shield (the outer wire
mesh of the cable) is grounded to the antenna base
and the radio receiver chassis.

The antenna coaxial cable has an additional dis-

connect, located near the inboard side of the glove
box opening on the back side of the lower instrument
panel

reinforcement.

This

additional

disconnect

allows the instrument panel assembly to be removed
and installed without removing the radio receiver.

The factory-installed Electronically Tuned Radios

(ETR) automatically compensate for radio antenna
trim. Therefore, no antenna trimmer adjustment is
required

or

possible

when

replacing

the

radio

receiver or the antenna.

RADIO NOISE SUPPRESSION

DESCRIPTION

Radio Frequency Interference (RFI) and Electro-

Magnetic Interference (EMI) noise suppression is
accomplished primarily through circuitry internal to

the

radio

receivers.

These

internal

suppression

devices are only serviced as part of the radio receiver.

External suppression devices that are used on this

vehicle to control RFI or EMI noise include the fol-
lowing:

• Radio antenna base ground

• Radio receiver chassis ground wire or strap

• Engine-to-body ground strap(s)

• Exhaust system-to-body ground strap (4.7L

engines only)

• Resistor-type spark plugs

• Radio suppression-type secondary ignition wir-

ing.

For more information on the spark plugs and sec-

ondary ignition components, refer to Ignition Sys-
tem in the Description and Operation section of
Group 8D - Ignition System.

DIAGNOSIS AND TESTING

AUDIO SYSTEM

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS,

REFER

TO

GROUP

8M

-

PASSIVE

RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING

WHEEL,

STEERING

COLUMN,

OR

INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

8F - 4

AUDIO SYSTEMS

DN

DESCRIPTION AND OPERATION (Continued)

Audio System Diagnosis

CONDITION

POSSIBLE CAUSE

CORRECTION

NO AUDIO

1. Fuse faulty.
2. Radio connector faulty.
3. Wiring faulty.
4. Ground faulty.
5. Radio faulty.
6. Speakers faulty.
7. Amplifier faulty (if
equipped).

1. Check radio fuses in junction block. Replace
faulty fuses, if required.
2. Check for loose or corroded radio connections.
Repair, if required.
3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Refer to Radio in the Diagnosis and Testing
section of this group.
6. Refer to Speaker in the Diagnosis and Testing
section of this group.
7. Refer to Speaker in the Diagnosis and Testing
section of this group.

NO DISPLAY

1. Fuse faulty.
2. Radio connector faulty.
3. Wiring faulty.
4. Ground faulty.
5. Radio faulty.

1. Check radio fuses in junction block. Replace
faulty fuses, if required.
2. Check for loose or corroded radio connections.
Repair, if required.
3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Refer to Radio in the Diagnosis and Testing
section of this group.

CLOCK WILL NOT KEEP
SET TIME

1. Fuse faulty.
2. Radio connector faulty.
3. Wiring faulty.
4. Ground faulty.
5. Radio faulty.

1. Check ignition-off draw fuse. Replace faulty
fuse, if required.
2. Check for loose or corroded radio connections.
Repair, if required.
3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Refer to Radio in the Diagnosis and Testing
section of this group.

POOR RADIO RECEPTION

1. Antenna faulty.
2. Ground faulty.
3. Radio faulty.
4. Faulty EMI or RFI noise
suppression.

1. Refer to Antenna in the Diagnosis and Testing
section of this group.
2. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
3. Refer to Radio in the Diagnosis and Testing
section of this group.
4. Refer to Radio Frequency Interference in the
Diagnosis and Testing section of this group.

NO/POOR TAPE
OPERATION

1. Faulty tape.
2. Foreign objects behind
tape door.
3. Dirty cassette tape head.
4. Faulty tape deck.

1. Insert known good tape and test operation.
2. Remove foreign objects and test operation.
3. Clean head with Mopar Cassette Head
Cleaner.
4. Exchange or replace radio, if required.

DN

AUDIO SYSTEMS

8F - 5

DIAGNOSIS AND TESTING (Continued)