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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Lighting System) >> Diagnostic Information and Procedures >> Backup Lamps Malfunction >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition OFF, disconnect the X1 harness connector at the body fuse block.
  2. Test for less than 5 Ω between the ground circuit terminal E2 and ground.
    • If greater then the specified range, test the ground circuit for and open/high resistance.
  3. Connect a test lamp between the control circuit terminal K8 and ground.
  4. Ignition ON, command the Backup Lamps 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 control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Ignition OFF, disconnect the appropriate backup lamp.
  6. Test for less than 5 Ω between the ground circuit terminal G and ground.
    • If greater than the specified range, test the ground circuit for a open/high resistance.
  7. Connect a test lamp between the control circuit terminal A and ground.
  8. Command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF between the commanded states.
    • If the test lamp is always ON, test the control circuit for short to voltage.
    • If the test lamp is always OFF, test the control circuit for a short to ground or and open/high resistance.
  9. If the circuits test normal, replace the body fuse block.
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