2024 GMC Terrain SLE, 4WDFACTORY OEM SERVICE PROCEDURE

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector for the appropriate A9 Outside Rearview Mirror. It may take up to 2 min for all vehicle systems to power down.
    • X510 - Driver Door Harness to Outside Rearview Mirror
    • X610 - Passenger Door Harness to Outside Rearview Mirror
  2. Test for less than 10 Ω between the ground circuit terminal 7 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition ON, connect a DMM between the control circuit terminal 19 and the ground circuit terminal 7.
  4. Verify voltage is between 0.5 V - 13 V when commanding the Object Detection Alert Indicators On and Off with a scan tool.
    • If voltage is less than 0.5 V. 
    1. Ignition OFF, disconnect the harness connector at the appropriate B218 Side Object Sensor Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the B218 Side Object Sensor Module.
    • Go to next step: If voltage is between 0.5 V - 13 V. 
  5. Verify voltage is less than 1 V when commanding the Object Detection Alert Indicators Off with a scan tool.
    • If voltage is greater than 1 V. 
    1. Ignition OFF, disconnect the harness connector at the B218 Side Object Sensor Module, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the B218 Side Object Sensor Module.
    • Go to next step: If voltage is less than 0.5 V. 
  6. Test or replace the A9 Outside Rearview Mirror Glass.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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