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Home >> Cadillac >> 2009 >> XLR Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 112 (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 Cadillac XLR. 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, 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. Connect a test lamp between the inoperative LED signal circuit and the ground circuit terminal 8.
  4. Command the appropriate LED ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the inoperative signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM.
    • If the test lamp is always OFF, test the inoperative 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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