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Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> External Pages >> Different car >> Section 111 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> OnStar Button LED Inoperative >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
  2. Ignition OFF, doors closed, interior lamps OFF, test for less than 5 ohms between the inside rearview mirror ground circuit terminal 8 and ground.
    • If greater than specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, command the appropriate LED OFF with a scan tool. Test for less than 1 volt between the appropriate LED signal circuit terminal 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.
  4. Command the appropriate LED ON with a scan tool. Test for greater than 9 volts between the appropriate LED signal circuit terminal and ground.
    • 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.
  5. If all circuits test normal, replace the inside rearview mirror.
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