LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 2018 >> Enclave Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 19 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> OnStar Button LED Malfunction >> Circuit/System Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia Limited, 2017 Chevrolet Traverse, and 2017 Buick Enclave. 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. Doors closed, courtesy lamps OFF, test for less than 10 Ω between the ground circuit terminal 8 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, command the green LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal 14 and ground.
    • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the CIM.
  4. Command the green LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal 14 and ground.
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM.
  5. Command the red LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal 15 and ground.
    • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the CIM.
  6. Command the red LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal 15 and ground.
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM.
  7. If all circuits test normal, replace the inside rearview mirror.