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Home >> GMC >> 2007 >> Acadia SLT, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 601 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> OnStar Button LED Inoperative >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Saturn Outlook, 2008 GMC Acadia, and 2008 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the inside rearview mirror harness connector.
  2. Ignition ON, test for 9.2 to 10.2 volts on terminal 12.
    • If less than the specified voltage repair short to ground or open or replace the VCIM.
  3. Test for less than 1 ohm between the inside rearview mirror harness connector terminal 8 and ground.
    • If greater than specified value repair open or high resistance.
  4. Connect a DMM between the inside rearview mirror harness connector terminal 14 and ground. With a scan tool command the green LED ON. Verify 9.2 to 10.2 volts is present with the green LED commanded ON.
    • If 9.2 to 10.2 volts is present with the green LED is commanded ON, replace the inside rearview mirror.
  5. Connect a DMM between the inside rearview mirror harness connector terminal 15 and ground. With a scan tool command the red LED ON. Verify 9.2 to 10.2 volts is present with the red LED commanded ON.
    • If 9.2 to 10.2 volts is present with the red LED is commanded ON, replace the inside rearview mirror.
  6. Disconnect the VCIM harness connector X1.
  7. Test for less than 1 volt between the X1 VCIM connector terminal 3 and the inside rearview mirror harness connector terminal 14.
    • If more than the specified value repair short to voltage on the keypad green LED signal circuit.
  8. Test for less than 1 volt between the X1 VCIM connector terminal 2 and the inside rearview mirror harness connector terminal 15.
    • If more than the specified value repair short to voltage on the keypad red LED signal circuit.
  9. Test for less than 1 ohm between the X1 VCIM connector terminal 3 and the inside rearview mirror harness connector terminal 14.
    • If more than the specified value repair open or high resistance on the keypad green LED signal circuit.
  10. Test for less than 1 ohm between the X1 VCIM connector terminal 2 and the inside rearview mirror harness connector terminal 15.
    • If more than the specified value repair open or high resistance on the keypad red LED signal circuit.
  11. If all circuits test normal, test or replace the VCIM.