Schematic Reference: Radio/Audio System Schematics

Always perform the Radio/Audio System Diagnostic System Check before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Radio/Audio System .

Important: The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Without RPO U80

1. Speaker output shorted - Test all speaker outputs for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. Defective radio - Replace the radio. Refer to Radio Replacement .

With RPO U80 (Bose)

1. Battery positive voltage circuit to the amplifier open. Test the battery positive voltage circuit to the amplifier for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. Low level audio signal circuit shorted. Test all low level audio signal circuits for a short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
3. 14 Volt reference circuit open or shorted to ground. Test the 14 volt reference circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
4. No low level audio output from the radio. Test for any AC voltage between the left front low level audio signal circuits at the amplifier harness connector, disconnected with the radio volume adjusted to 50 %. If no AC voltage is present, replace the radio. Refer to Radio Replacement .
5. No audio output from the amplifier. Replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

Important: The following information lists the most probable cause of the concern to the least probable cause. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Without RPO U80

1. Speaker output open. Test the appropriate speaker output circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. No audio output from the radio. Test for any AC voltage between the appropriate speaker output circuits at the speaker harness connector, disconnected with the radio volume adjusted to an audible level. If AC voltage is present, replace the speaker. Refer to Speaker Replacement Reference . If no AC voltage is present, replace the radio. Refer to Radio Replacement .

With RPO U80 (Bose)

1. Speaker output circuit from amplifier open or shorted. Test the appropriate speaker output circuits for an open or short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. No audio output from the amplifier. Test for any AC voltage between the appropriate speaker output circuits at the speaker harness connector, disconnected with the radio volume adjusted to an audible level. If AC voltage is present, replace the speaker. Refer to Speaker Replacement Reference . If no AC voltage is present, replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

Important: The following information lists the most probable cause of the concern to the least probable cause. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Without RPO U80

1. Speaker output circuit high resistance. Test the appropriate speaker output circuits for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. Defective speaker - Replace the appropriate speaker. Refer to Speaker Replacement Reference .

With RPO U80 (Bose)

1. Speaker output circuit high resistance. Test the appropriate speaker output circuits for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
2. Low level audio circuit open. Test the appropriate low level audio circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
3. Defective speaker - Replace the appropriate speaker. Refer to Speaker Replacement Reference .