GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit / System Description

The video entertainment system in this vehicle transmits the DVD audio signal playback to the vehicle via an FM modulation process. The DVD audio signals are routed through the a/v box, through the audio filter and on to the FM modulator. The tuner on the radio is then tuned to one of the selectable frequencies on the FM frequency selector switch inside the console. The DVD audio portion can now be heard through the vehicle audio system. For the clearest sound reproduction from the DVD Audio, tune the radio to each one of the frequencies shown on the FM frequency selector switch and stop on the frequency that has the least amount of radio signal or noise. Now set the FM frequency selector switch to the same frequency as the radio.

Reference Information

Schematic Reference

Video System Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

DVD Vehicle Audio Playback Inoperative

  1. Turn ON the ignition, Tune the radio to station 88.5, 88.7, 88.9, 89.1,89.3, 89.5, 89.7, or 89.9, MHz. Chose the station that has the least amount of regular audible radio reception or noise.
  2. Turn ON the FM frequency selector switch and select the same frequency that the radio is tuned to.
  3. Press the power button on the headrest DVD display(s). Insert a DVD and operate the DVD player in play mode. Verify the DVD audio can not received on one of the above stations.
  4. If the DVD audio can be heard review the system operation with the customer.
  5. Verify the DVD player is in play mode and the proper source is selected at the DVD display screens.
  6. At the DVD player , test for AC voltage on all the audio left and right circuits with a DMM.
  7. If AC voltage is not present, test the appropriate circuit for an open / high resistance , or short to ground or short to power.
    If the circuits test normal, replace the DVD control module.
  8. Test for AC voltage on the audio left and right circuits to audio ground, between the A/V box and the audio filter.
  9. If AC voltage is not present, test the appropriate circuit for an open / high resistance , or short to ground or short to power.
    If the circuits test normal, replace the audio filter.
  10. Test for AC voltage on the audio left and right circuits to audio ground, between the audio filter and the FM modulator.
  11. If AC voltage is not present, test the appropriate circuit for an open / high resistance , or short to ground or short to power.
    If the circuits test normal, replace the FM Modulator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to the accessory installation instructions for replacement.