Jeep Grand Cherokee ZJ Audio System.pdf

AUDIO SYSTEMS

8F - 1

AUDIO SYSTEMS

CONTENTS

page

GENERAL INFORMATION .................. 1

POWER ANTENNA RELAY ................ 12

POWER RADIO ANTENNA ................ 11

SERVICE PROCEDURES ................... 8

STANDARD RADIO ANTENNA .............. 10

TEST PROCEDURES ...................... 2

GENERAL INFORMATION

DESCRIPTION

For operation of the factory installed radios refer to

the Owners Manual supplied with the vehicle.

All radios receive IGN feed from the 10 amp #10

RADIO fuse.

All vehicles are equipped with an Ignition-Off Draw

(IOD) fuse which is used when the vehicles are origi-

nally shipped from the factory. This fuse #F1, which

is located in the Power Distribution Center, helps to

prevent battery discharge during storage. For specific

location refer to Group 8W - Wiring Diagrams.

The IOD fuse includes the radio memory circuitry

and should be checked if the memory (time or radio

station programming) is inoperative.

The radio is connected to fuse #8 in order to retain

the radio’s memory when the ignition switch is

turned to OFF.

The electronically tuned (ETR) radio is self

compensating. A radio trimmer adjustment is

not required.

deteriorated spark plug wires should be replaced.

RADIO NOISE DIAGNOSIS

INTERFERENCE ELIMINATION

A number of components are used on vehicles

equipped with a radio, to suppress radio frequency

interference (static).

Capacitors are mounted in the generator and power

mirror motors.

Radio resistance type spark plugs in the high ten-

sion circuit of the ignition system complete the inter-

ference suppression.

If radio noises are evident, isolate circuits with

capacitors to be sure they are the cause. Faulty or

8F - 2 AUDIO SYSTEMS

TEST PROCEDURES

RADIO DIAGNOSIS

AUDIO SYSTEMS 8F - 3

RADIO SCHEMATIC

8F - 4 AUDIO SYSTEMS

SPEAKER DIAGNOSIS

AM/FM/STEREO—STEREO CASSETTE

(2) Move balance and fader control to Left Front,

Right Front, Right Rear, and Left Rear. If sound is

heard from any speaker during any of these positions

there is a short in one of the speaker feed wires.

(a) If front speakers have normal sound; one rear

speaker has low sound and the other has no sound,

then the speaker with low sound has a short in its

feed line. Check wires to BLACK connector pins 5

and 6 for shorts to vehicle chassis.

(b) If rear speakers have normal sound; one front

speaker has low sound and the other has no sound,

then the speaker with low sound has a short in its

Short Circuits

On some radios, if a speaker wire is shorted the

audio output will automatically shut down. Turn

fader and balance controls to mid position and volume

at mid position. If display operates and there is no

volume from any speaker proceed to the Short test.

Short Circuit Test

(1) Turn radio on to mid volume.

AUDIO SYSTEMS

8F - 5

feed line. Check wires to BLACK connector pins 3

and 4 for shorts to vehicle chassis.

(3) If no sound is heard while adjusting the balance

and fader controls there still may be a short in one of

the 4 speaker return lines. Check speaker wires con-

nected to GRAY connector pins 5 and 6 for shorts to

vehicle chassis.

(4) If all the tests show no problem, replace radio.

ANTENNA TESTING

ANTENNA DIAGNOSIS

Fig. 1 Antenna Test Points

Antenna performance may be tested by substituting

a known good antenna. Check short or open circuits

with an ohmmeter or continuity light once the an-

tenna cable is disconnected from the radio as follows:

(1) Continuity should be observed between the tip

of the mast and radio end pin (Fig. 1).

(2) No continuity or a very high resistance of sev-

eral megohms should be observed between the ground

shell of the connector and radio end pin.

(3) Continuity should be observed between the

ground shell of the connector and the mounting hard-

ware on the fender.

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