GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

Connector End Views Reference: Entertainment Connector End Views

Diagnostic System Check - Vehicle

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

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.

Without RPO UZ8

  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 Control Module References in Computer/Integrating Systems.

With RPO UZ8 (Monsoon)

  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 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 Control Module References in Computer/Integrating Systems.

Speakers - One Channel Inoperative

Important: Channel 1 refers to the front door speakers and the rear subwoofers.

Channel 2 refers to the rear door speakers and the front instrument panel (I/P) tweeters.

With RPO UZ8

  1. Speaker or subwoofer output shorted--Test the appropriate outputs from the amplifier for a short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Defective amplifier--Replace the amplifier. Refer to Radio Speaker Amplifier Replacement in Entertainment.

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

With RPO U2K

  1. Left or right audio signal (+) circuit open--Test the appropriate 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 Control Module References in Computer/Integrating Systems.
  3. No digital radio output from the radio--Replace the radio. Refer to Control Module References in Computer/Integrating Systems.