Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC2020SAVANA 3500 LS, VAN PASSENGER, 6.0L ENG VIN B, GAS/ETHANOLREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEBODY, CAB CONTROL SYSTEMSVEHICLE ACCESS SYSTEMDIAGNOSTIC INFORMATION AND PROCEDURESACCESS PANEL RELEASE MALFUNCTIONCIRCUIT/SYSTEM TESTING
2020 GMC Savana 3500 LS, Van Passenger, 6.0L Eng VIN B, Gas/Ethanol
Circuit/System Testing
2020 GMC Savana 3500 LS, Van Passenger, 6.0L Eng VIN B, Gas/EthanolSECTION Circuit/System Testing
Right Access Panel Malfunction
- Ignition OFF, disconnect the Right Access Panel relay.
- 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.
- 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.
- 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.
- 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.
- Connect a test lamp between the B+ circuit terminal 15 and the control circuit terminal 13.
- 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.
- If all circuits test normal, test or replace the Right Access Panel relay.
Left Front Access Panel Malfunction
- Ignition OFF, disconnect the Left Front Access Panel relay.
- 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.
- 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
- 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.
- 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.
- Connect a test lamp between the B+ circuit terminal 5 and the control circuit terminal 3.
- 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.
- If all circuits test normal, test or replace the Left Front Access Panel relay.
Left Rear Access Panel Malfunction
- Ignition OFF, disconnect the Left Rear Access Panel relay.
- 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.
- 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.
- 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.
- 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.
- Connect a test lamp between the B+ circuit terminal 10 and the control circuit terminal 8.
- 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.
- If all circuits test normal, test or replace the Left Rear Access Panel relay.
Access Panel Actuator Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate access panel actuator.
- Test for less than 1 Ξ© between the ground circuit terminal 4 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, connect a test lamp between the control circuit terminal 3 and ground.
- 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.
- If all circuits test normal, test or replace the access panel release actuator.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.