Circuit/System Testing

2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Crew Cab Sunroof Switch Test

  1. Disconnect the sunroof switch connector.
  2. Verify less than 1 ohm of resistance from the ground circuit terminal 5 and ground.
    • If the resistance is greater than the specified value, repair the ground circuit for an open/high resistance.
  3. Ignition on, connect a fused jumper wire from the ground circuit terminal 5 in the harness connector to the open signal circuit terminal 6 and verify that the sunroof opens.
    • If the sunroof does not open perform the Sunroof Motor/Actuator Circuit Test.
  4. Connect a fused jumper wire from the ground circuit terminal 5 to the close signal circuit terminal 4 and verify that the sunroof closes.
    • If the sunroof does not close perform the Sunroof Motor/Actuator Circuit Test.
  5. Connect a fused jumper wire from the ground circuit terminal 5 to the vent open signal circuit terminal 2 and verify that the sunroof vent opens.
    • If the sunroof does not vent open perform the Sunroof Motor/Actuator Circuit Test.
  6. Connect a fused jumper wire from the ground circuit terminal 5 to the vent close signal circuit terminal 8 and verify that the sunroof vent closes.
    • If the sunroof does not vent close perform the Sunroof Motor/Actuator Circuit Test.
  7. Connect a fused jumper wires from the ground circuit terminal 5 to the express signal circuit terminal 1 the open signal circuit terminal 6 and verify that the sunroof express opens.
    • If the sunroof does not express open perform the Sunroof Motor/Actuator Circuit Test.
  8. Connect a fused jumper wires from the ground circuit terminal 5 to the express signal circuit terminal 1 the close signal circuit terminal 4 and verify that the sunroof express closes.
    • If the sunroof does not express close perform the Sunroof Motor/Actuator Circuit Test.
  9. If the circuits test normal replace the sunroof switch.

Extended Cab Sunroof Switch Circuit Test

  1. Disconnect the sunroof switch connector.
  2. Verify less than 1 ohm of resistance from the ground circuit terminal 5 and ground.
    • If the resistance is greater than the specified value, repair the ground circuit for an open/high resistance.
  3. Ignition on, connect a fused jumper wire from the ground circuit terminal 5 in the harness connector to the open signal circuit terminal 6 and verify that the sunroof opens.
    • If the sunroof does not open perform the Sunroof Motor/Actuator Circuit Test.
  4. Connect a fused jumper wire from the ground circuit terminal 5 to the close signal circuit terminal 4 and verify that the sunroof closes.
    • If the sunroof does not close perform the Sunroof Motor/Actuator Circuit Test.
  5. Connect a fused jumper wires from the ground circuit terminal 5 to the express signal circuit terminal 1 the open signal circuit terminal 6 and verify that the sunroof express opens.
    • If the sunroof does not express close perform the Sunroof Motor/Actuator Circuit Test.
  6. If the circuits test normal replace the sunroof switch.

Sunroof Motor/Actuator Circuit Test

  1. Disconnect the sunroof motor/actuator connector.
  2. Verify less than 1 ohm of resistance from the ground circuit terminal 1 and ground.
    • If the resistance is greater than the specified value, repair the ground circuit for an open/high resistance.
  3. Connect a test lamp from the ground circuit terminal 1 to the battery supply circuit terminal 6 and verify that the test lamp illuminates.
    • If the test lamp does not illuminate, repair the battery supply circuit for an open/high resistance or short to ground.
  4. Ignition on, connect a test lamp from the ground circuit terminal 1 to the ignition supply circuit terminal 6 and verify that the test lamp illuminates.
    • If the test lamp does not illuminate, repair the ignition supply circuit for an open/high resistance or short to ground.
  5. Connect the sunroof motor/actuator connector and disconnect the sunroof switch connector.
  6. Ignition on, verify that battery voltage is present at each of the switch signal circuit terminals in the switch harness connector.
    • If battery voltage is not present at all of the signal circuits, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal replace the sunroof motor/actuator.
  7. If the circuit tests normal replace the sunroof motor/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.