GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

All Speakers Inoperative

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.

With RPO U62

  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 Radio. Refer to Radio Replacement .

With RPO UQ3

  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. Ground circuit to the amplifier open. Test the ground circuit to the amplifier for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  3. Antenna enable signal circuit to the amplifier open or shorted to ground. Test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  4. No audio output from the amplifier. Replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

One Speaker Inoperative

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.

With RPO U62

  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 Radio Rear Speaker Replacement or Radio Front Side Door Speaker Replacement . If no AC voltage is present, replace the radio. Refer to Radio Replacement .

With RPO UQ3

  1. Speaker output circuit from amplifier 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 amplifier. Test for any AC voltage between the appropriate speaker output circuits at the speaker harness connector, disconnected with the radio volume adjusted to 50 percent. If AC voltage is present, replace the speaker. Refer to Radio Rear Speaker Replacement or Radio Front Side Door Speaker Replacement . If no AC voltage is present, replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

Speakers - One Channel Inoperative

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.

With RPO U62

  1. Speaker output circuit from amplifier open shorted. Test the appropriate speaker output circuits for a 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 50 percent. If AC voltage is present, replace the speaker. Refer to Radio Rear Speaker Replacement or Radio Front Side Door Speaker Replacement . If no AC voltage is present, replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

Speakers - Reduced Volume

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.

With RPO U62

  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 Radio Rear Speaker Replacement or Radio Front Side Door Speaker Replacement .

With RPO UQ3

  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 Radio Rear Speaker Replacement or Radio Front Side Door Speaker Replacement .