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Home >> Saturn >> 2008 >> Sky Red Line, Automatic >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Infotainment >> Cellular System, Entertainment System, And Navigation System >> Diagnostic Information & Procedures >> OnStar Microphone Inoperative - Caller Cannot Be Heard >> Circuit/System Description >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the cellular microphone.
  2. Ignition OFF, test for less than 5 ohms between the drain wire circuit terminal A and ground.
    • If greater than the specified range, test the drain wire circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the VCIM.
  3. Ignition ON, test for 9.5-10.5 volts between the cellular microphone signal circuit terminal B and ground.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the VCIM.
  4. If all circuits test normal, replace the cellular microphone.