GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment/Communication Connector End Views

Diagnostic System Check - Vehicle

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

Left Channel - Audio Distortion

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.

Left Front Low Level Audio Signal circuit open - Test the left front low level audio signal circuits for an open. Refer to Circuit Testing and Wiring Repairs.

Right Channel - Audio Distortion

Right Front Low Level Audio Signal circuit open - Test the right front low level audio signal circuits for an open. Refer to Circuit Testing and Wiring Repairs.

One Speaker - Audio Distortion

  1. Speaker output from Amplifier open or shorted to voltage - Test the appropriate speaker output for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs.
  2. Defective speaker - Replace the appropriate speaker. Refer to Speaker Replacement Reference.
  3. Defective Amplifier - Replace the Amplifier. Refer to Control Module References for Replacement, Setup or Programming.

Audio Distortion from Rear Speaker During 5.1 DSS DVD Playback

Audio output from radio open - Test the appropriate output from the radio for an open. Refer to Circuit Testing and Wiring Repairs.