Jeep Grand Cherokee WJ. Manual - part 112

ter (6.5 inch) diameter full-range speaker located in
each rear door.

PREMIUM

The optional premium speaker system features six

Infinity model speakers in six locations. Each of the
standard speakers is replaced with Infinity model
speakers. One 6.4 centimeter (2.50 inch) diameter
Infinity tweeter is installed on each end of the
instrument panel top pad. One 15.2 by 22.9 centime-
ter (6 by 9 inch) Infinity woofer is located in each
front door. There is also one full-range 16.5 centime-
ter (6.5 inch) diameter Infinity full-range speaker
located in each rear door. The premium speaker sys-
tem also includes an additional Infinity power ampli-
fier. The total available power of the premium
speaker system is about 180 watts.

OPERATION

STANDARD

Each of the two tweeters and four full-range speak-

ers 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 System in the Contents of Group 8W - Wir-
ing Diagrams.

PREMIUM

The six 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 180 watts out-
put. The power amplifier unit is mounted to the rear
floor panel under the passenger side rear seat cush-
ion. The power amplifier unit can be accessed for ser-
vice by unlatching and tilting the passenger side rear
seat cushion forward.

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 is energized by a fused 12 volt

output from the radio receiver whenever 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 out-
puts for each of those channels to the six Infinity
speakers. For complete circuit diagrams, refer to
Audio System in the Contents of Group 8W - Wir-
ing Diagrams.

ANTENNA

DESCRIPTION

All models use a fixed-length stainless 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 passenger side cowl side
inner panel behind the lower instrument panel rein-
forcement. 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

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

and

transmission

ground strap (4.7L engines only)

• Resistor-type spark plugs

• Radio suppression-type secondary ignition wir-

ing.

8F - 4

AUDIO SYSTEMS

DESCRIPTION AND OPERATION (Continued)

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

GROUP

PASSIVE

RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING

WHEEL,

STEERING

COLUMN,

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

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.

AUDIO SYSTEMS

8F - 5

DESCRIPTION AND OPERATION (Continued)

AUDIO SYSTEM DIAGNOSIS

CONDITION

POSSIBLE CAUSE

CORRECTION

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.

NO COMPACT DISC
OPERATION

1. Faulty CD.
2. Foreign material on CD.
3. Condensation on CD or optics.
4. Faulty CD player.

1. Insert known good CD and test operation.
2. Clean CD and test operation.
3. Allow temperature of vehicle interior to stabilize
and test operation.
4. Exchange or replace radio, if required.

NO COMPACT DISC
CHANGER
OPERATION

1. Faulty CD.
2. Foreign material on CD.
3. Condensation on CD or optics.
4. CD changer connector faulty.
5. Wiring faulty.
6. PCI data bus faulty.
7. CD changer faulty.

1. Insert known good CD and test operation.
2. Clean CD and test operation.
3. Allow temperature of vehicle interior to stabilize
and test operation.
4. Check for loose or corroded CD changer
connections. Repair, if required.
5. Refer to Compact Disc Changer in the
Diagnosis and Testing section of this group.
6. Use DRB scan tool and the Diagnostic
Procedures manual to test PCI data bus. Repair,
if required.
7. Refer to Compact Disc Changer in the
Diagnosis and Testing section of this group.

RADIO RECEIVER

If the vehicle is equipped with the optional remote

radio switches located on the steering wheel and the
problem being diagnosed is related to one of the
symptoms listed below, be certain to check the
remote radio switches and circuits. Refer to Remote
Radio Switch in the Diagnosis and Testing section

of this group prior to attempting radio diagnosis or
repair.

• Stations changing with no remote radio switch

input

• Radio memory presets not working properly

• Volume changes with no remote radio switch

input

8F - 6

AUDIO SYSTEMS

DIAGNOSIS AND TESTING (Continued)

• Remote radio switch buttons taking on other

functions

• CD player skipping tracks

• Mode (AM, FM, CD, CD changer) changes with

no remote radio switch input

• Remote radio switch inoperative.
For complete circuit diagrams, refer to Audio Sys-

tem in the Contents of Group 8W - Wiring Diagrams.

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS,

REFER

GROUP

PASSIVE

RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING

WHEEL,

STEERING

COLUMN,

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

CAUTION: The speaker output of the radio receiver
is a “floating ground” system. Do not allow any
speaker lead to short to ground, as damage to the
radio receiver may result.

(1) Check the fused B(+) fuse in the junction block.

If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.

(2) Check for battery voltage at the fused B(+) fuse

in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the Power Dis-
tribution Center (PDC) fuse as required.

(3) Check the fused ignition switch output (acc/

run) fuse in the junction block. If OK, go to Step 4. If
not OK, repair the shorted circuit or component as
required and replace the faulty fuse(s).

(4) Turn the ignition switch to the On position.

Check for battery voltage at the fused ignition switch
output (acc/run) fuse in the junction block. If OK, go
to Step 5. If not OK, repair the open fused ignition
switch output (acc/run) circuit to the ignition switch
as required.

(5) Turn the ignition switch to the Off position.

Disconnect and isolate the battery negative cable.
Remove the radio receiver from the instrument
panel, but do not disconnect the wire harness connec-
tors. Check for continuity between the radio receiver
chassis and a good ground. There should be continu-
ity. If OK, go to Step 6. If not OK, repair the open
ground circuit to ground as required.

(6) Test the radio receiver antenna. Refer to

Antenna in the Diagnosis and Testing section of this
group. If OK, go to Step 7. If not OK, replace the
faulty antenna or coaxial cable as required.

(7) Connect the battery negative cable. Turn the

ignition switch to the On position. Check for battery

voltage at the fused ignition switch output (acc/run)
circuit cavity of the left (gray) radio wire harness
connector. If OK, go to Step 8. If not OK, repair the
open fused ignition switch output (acc/run) circuit to
the junction block fuse as required.

(8) Turn the ignition switch to the Off position.

Check for battery voltage at the fused B(+) circuit
cavity of the left (gray) radio wire harness connector.
If OK, replace the faulty radio receiver. If not OK,
repair the open fused B(+) circuit to the junction
block fuse as required.

COMPACT DISC CHANGER

Following are tests that will help to diagnose the

hard wired components and circuits of the Compact
Disc (CD) changer unit. However, these tests may not
prove conclusive in the diagnosis of this unit. In
order to obtain conclusive testing of the CD changer
unit, the Programmable Communications Interface
(PCI) data bus network, the CD changer unit, the
radio receiver unit and any other electronic modules
that provide inputs to, or receive outputs from the
audio system must be checked.

The most reliable, efficient, and accurate means to

diagnose

the

changer

messaging

functions

requires the use of a DRB scan tool and the proper
Diagnostic Procedures manual. The DRB scan tool
can provide confirmation that the PCI data bus is
functional, that all of the electronic modules in the
vehicle are sending and receiving the proper mes-
sages on the PCI data bus, and that the CD changer
and the radio receiver are receiving the proper PCI
messages to perform their audio system functions.

For complete circuit diagrams, refer to Audio Sys-

tem in the Contents of Group 8W - Wiring Diagrams.

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS,

REFER

GROUP

PASSIVE

RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING

WHEEL,

STEERING

COLUMN,

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

COMPACT DISC CHANGER INOPERATIVE

(1) Turn the ignition switch to the On position.

Turn the radio receiver on and check its operation. If
OK, go to Step 2. If not OK, refer to Radio Receiver
in the Diagnosis and Testing section of this group.

(2) Turn the ignition switch to the Off position. Dis-

connect and isolate the battery negative cable. Discon-
nect the right body wire harness connector from the CD
changer connector receptacle. Check for continuity
between the power ground (Z17) circuit of the right

AUDIO SYSTEMS

8F - 7

DIAGNOSIS AND TESTING (Continued)

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