Each of the audio output channel circuits (+) and (-), at the radio and at the amplifier (if equipped) have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1V AC and less, where constant music may measure 3V AC and slightly higher. In an amplified audio system, these similar AC voltage measurements may be slightly higher on the output of the amplifier, and the typical AC voltage readings at the output of the radio are less than 1V AC.

The radio is ON.

A short to voltage or a short to ground is detected on a speaker output signal circuit.

The radio disables its outputs on one or more channels, producing no sound.

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for Scan Tool information.

Radio ON, adjust the fade and balance controls on the radio to test all four channels individually. All speakers should function properly.

Without Amplifier

1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

4. If all circuits test normal, replace the speaker.

With Amplifier

1. Ignition OFF, disconnect the X3 connector at the amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

•	Left front low audio signal (+) - terminal 1

•	Left front low audio signal (-) - terminal 2

•	Right front low audio signal (+) - terminal 10

•	Right front low audio signal (-) - terminal 9

•	Left rear low audio signal (+) - terminal 4

•	Left rear low audio signal (-) - terminal 3

•	Right rear low audio signal (+) - terminal 11

•	Right rear low audio signal (-) - terminal 12

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. If all circuits test normal, replace the amplifier.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.