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Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the radio.
  2. Ignition ON, test for a varying AC voltage between the following signal circuit terminals listed below and ground when the OnStar® Call Center button is pressed.
    • Audio Signal Circuit- terminal 7
    • Audio Common Circuit- terminal 15
    • If AC voltage was not present, test the circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the CIM.
  3. If all circuits test normal, replace the radio.