GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

Diagnostic System Check - Entertainment System

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

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.

Without RPO UQA

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

With RPO UQA (Bose)

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