Circuit/System Testing

2019 Chevrolet Blazer Premier, FWDSECTION Circuit/System Testing
  1. Ignition OFF, disconnect the X2 harness connector at the K171 Hands-Free Liftgate Sensor Control Module.
  2. Test for less than 1 V between the B275A Hands-Free Liftgate Sensor - Upper signal circuit terminal 1 and ground
    • If 1 V or greater 

      Replace the B275A Hands-Free Liftgate Sensor - Upper

    • Go to next step: If less than 1 V 
  3. Test for less than 1 V between the B275A Hands-Free Liftgate Sensor - Upper signal circuit terminal 2 and ground
    • If 1 V or greater 

      Replace the B275A Hands-Free Liftgate Sensor - Upper

    • Go to next step: If less than 1 V 
  4. Test for infinite resistance between the B275A Hands-Free Liftgate Sensor - Upper signal circuit terminal 1 and ground.
    • If not the specified value 

      Replace the B275A Hands-Free Liftgate Sensor - Upper

    • Go to next step: If infinite resistance 
  5. Test for infinite resistance between the B275A Hands-Free Liftgate Sensor - Upper signal circuit terminal 2 and ground.
    • If not the specified value 

      Replace the B275A Hands-Free Liftgate Sensor - Upper

    • Go to next step: If infinite resistance 
  6. Test for less than 1 Ω between the B275A Hands-Free Liftgate Sensor - Upper signal circuit terminal 1 and the signal circuit terminal 2.
    • If 1 Ω or greater 

      Replace the B275A Hands-Free Liftgate Sensor - Upper

    • Go to next step: If less than 1 Ω 
  7. Ignition OFF, disconnect the X3 harness connector at the K171 Hands-Free Liftgate Sensor Control Module.
  8. Test for less than 1 V between the B275B Hands-Free Liftgate Sensor - Lower signal circuit terminal 1 and ground
    • If 1 V or greater 

      Replace the B275B Hands-Free Liftgate Sensor - Lower

    • Go to next step: If less than 1 V 
  9. Test for less than 1 V between the B275B Hands-Free Liftgate Sensor - Lower signal circuit terminal 2 and ground
    • If 1 V or greater 

      Replace the B275B Hands-Free Liftgate Sensor - Lower

    • Go to next step: If less than 1 V 
  10. Test for infinite resistance between the B275B Hands-Free Liftgate Sensor - Lower signal circuit terminal 1 and ground.
    • If not the specified value 

      Replace the B275B Hands-Free Liftgate Sensor - Lower

    • Go to next step: If infinite resistance 
  11. Test for infinite resistance between the B275B Hands-Free Liftgate Sensor - Lower signal circuit terminal 2 and ground.
    • If not the specified value 

      Replace the B275B Hands-Free Liftgate Sensor - Lower

    • Go to next step: If infinite resistance 
  12. Test for less than 1 Ω between the B275B Hands-Free Liftgate Sensor - Lower signal circuit terminal 1 and the signal circuit terminal 2.
    • If 1 Ω or greater 

      Replace the B275B Hands-Free Liftgate Sensor - Lower

    • Go to next step: If less than 1 Ω 
  13. If all circuits test normal, replace the K171 Hands-Free Liftgate Sensor Control Module.
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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.