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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 19 (Vehicle Access System) >> Diagnostic Information and Procedures >> Access Panel Release Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Right Access Panel Malfunction

  1. Ignition OFF, disconnect the Right Access Panel relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 12 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 15 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 11 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Connect a 15 A fused jumper wire between the B+ circuit terminal 11 and the control circuit terminal 12. Verify that both actuators are activated.
    • If the actuators do not activate, test the control circuit for an short to ground or an open/high resistance. If the circuit tests normal, test or replace the actuators.
  6. Connect a test lamp between the B+ circuit terminal 15 and the control circuit terminal 13.
  7. Command the Right Side Rear Access Panel 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 ground. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the Right Access Panel relay.

Left Front Access Panel Malfunction

  1. Ignition OFF, disconnect the Left Front Access Panel relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 2 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance
  4. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Connect a 15 A fused jumper wire between the B+ circuit terminal 1 and the control circuit terminal 2. Verify that both actuators are activated.
    • If the actuators do not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the actuators.
  6. Connect a test lamp between the B+ circuit terminal 5 and the control circuit terminal 3.
  7. Command the Left From Access Panel 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 ground. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the Left Front Access Panel relay.

Left Rear Access Panel Malfunction

  1. Ignition OFF, disconnect the Left Rear Access Panel relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 7 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 10 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Connect a 15 A fused jumper wire between the B+ circuit terminal 6 and the control circuit terminal 7. Verify the both actuators are activated.
    • If the actuators do not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the actuators.
  6. Connect a test lamp between the B+ circuit terminal 10 and the control circuit terminal 8.
  7. Command the Left Side Rear Access Panel 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 ground. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the Left Rear Access Panel relay.

Access Panel Actuator Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate access panel actuator.
  2. Test for less than 1 Ω between the ground circuit terminal 4 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, connect a test lamp between the control circuit terminal 3 and ground.
  4. Command the access panel to release with a scan tool, the test lamp should illuminate during the release command.
    • If the test lamp is always ON, test the control circuit for a short to voltage.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance.
  5. If all circuits test normal, test or replace the access panel release actuator.
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