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.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

No Audio From Wireless Headphones

    Important: Center the balance and fade adjustment on the radio. If adjustment of the fade and balance eliminates the concern, review the operation of the radio with the customer.

  1. Turn ON the wireless headphones. Verify the power indicator lamp on the wireless headphone illuminates.
  2. If the power indicator lamp does not illuminate on the wireless headphones check or replace the wireless headphone batteries. If the batteries are OK replace the wireless headphones.
  3. Activate the RSA. Set both wireless headphones to the proper channel to hear RSA. Adjust the volume up on both wireless headphones. Verify that only one set of wireless headphones operate properly.
  4. If only one set of wireless headphones do not have audio, replace the suspect wireless headphone set.
  5. With a DMM, verify there is B+ at the infra-red module supply voltage circuit when the RSA is activated.
  6. If B+ is not present, test for a open or short to power on the infra-red module supply voltage circuit. If the infra-red module supply voltage circuit tests normal, replace the rear HVAC control module.
  7. At the infra-red module connector harness, test for AC voltage between the low reference circuit and the left and right infra-red audio signal circuits. Verify there is AC voltage with the RSA activated.
  8. If AC voltage is not present, test for an open, short to ground or short to B+ on the low reference and both left and right infra-red audio signal circuits. If the low reference and audio signals test normal replace the rear HVAC control module.
  9. Ignition OFF, Disconnect the harness connector of the infra-red module. Test for less than 1.0 ohm of resistance between the ground circuit terminal 12 and ground.
  10. If greater than the specified range, repair the ground circuit.
    If the ground circuit tests normal, replace the infra-red module.

Audio In One Channel of the Wireless Headphones or Distortion

    Important: Center the balance and fade adjustment on the radio. If adjustment of the fade and balance eliminates the concern, review the operation of the radio with the customer.

  1. Activate the RSA. Set both wireless headphones to the proper channel to hear RSA. Adjust the volume up on both wireless headphones. Verify that only one set of wireless headphones operates properly.
  2. If only one set of wireless headphones is faulty, replace the suspect wireless headphone set.
  3. At the infra-red module connector harness, test for AC voltage between the low reference circuit and the left and right infra-red audio signal circuits. Verify there is AC voltage with the RSA activated.
  4. If AC voltage is not present, test for an open, short to ground or short to B+ on the low reference and both left and right infra-red audio signal circuits. If the low reference and audio signals test normal replace the rear HVAC control module.
  5. Test for an open, short to ground or short to B+ on the low reference and both left and right infra-red audio signal circuits.
  6. If the low reference and audio signals test normal replace the infra-red module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Auxiliary Heater and Air Conditioning Control Module Replacement
    •  Audio System Transceiver Module Replacement