Radio Inoperative or OnStar Will Not Mute and, or Remote CD No Audio

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Radio will not mute and switch to OnStar Audio when in use. Also, if equipped with remote audio device (cassette or CD), the remote device will be inoperative.

1. The concern may be caused by the E and C wire dark green wire (circuit 835) shorted to ground.
2. If the radio has been removed and a replacement of any kind, especially a remanufactured unit has been installed, this "new" radio may not be OnStar compliant. If the replacement radio is not OnStar compliant, the radio will not mute when OnStar is used. It is not a requirement that the replacement radio be new. The correct remanufactured unit will correct this condition.

NOTE: Make sure the correct radio is installed in the vehicle which is OnStar compliant. If a radio has been replaced previously for any reason, this may be the problem.

If normal diagnostics do not find concern, perform the following circuit replacement.

1. Remove terminal 15 on radio connector C2, Terminal 14 on radio connector C3 and terminal A3 on OnStar VIU Red Connector C1.
2. Install a new wire from Terminal A3 connector C1 on VIU to radio connector C3 terminal 14 with a splice to terminal 14 at the CD player if equipped.
3. Install all connectors and retest system for mute with OnStar button press.

If concern is gone, there is damage to to one of the E and C circuits

Reinstall the wire removed from terminal 15 on radio connector C2 back in connector and retest. If concern returns, inspect E and C circuit from radio connector C2 terminal 15 to DLC for damage or short to ground. Replace as per above procedure making sure the new wiring does not rub or in anyway become damaged once installed.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.