GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

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 50 percent. 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 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 Speaker Replacement Reference . 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 UQ3

  1. Speaker output circuit from amplifier 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 Speaker Replacement Reference . If no AC voltage is present, replace the amplifier. Refer to Radio Speaker Amplifier Replacement .

Important: The following procedure assumes all speakers are operative for all modes of operation except digital radio.

With RPO U2K or U2L

  1. Remote radio audio signal circuit open. Test the appropriate remote radio audio signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. No audio output from the digital radio receiver. Replace the digital radio receiver. Refer to Digital Radio Receiver Replacement .
  3. No digital radio audio output from the radio. Replace the radio. Refer to Radio Replacement .