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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 980 (Sunroof System) >> Diagnostic Information and Procedures >> Power Sunroof Inoperative >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Power Sunroof Malfunction

  1. Disconnect the sunroof switch connector.
  2. Verify that a test lamp illuminates between the ground circuit terminal 5 and B+.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, connect a 3A fused jumper wire between the signal circuit listed below and ground. The sunroof should be inoperative in at least one or more directions.
    • Sunroof open terminal 6
    • Sunroof close terminal 4
    • Vent open (Crew Cab) terminal 2
    • Vent close (Crew Cab) terminal 8
    • If the sunroof moved in all directions, replace the sunroof switch.
  4. Ignition OFF, disconnect the harness connector at the sunroof motor/actuator.
  5. Verify that a test lamp illuminates between the ground circuit terminal 1 and B+.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  6. 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 a short to ground or an open/high resistance.
  7. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, refer to Power Mode Mismatch .
  8. Ignition OFF, connect the sunroof motor/actuator harness connector.
  9. Ignition ON, at the sunroof switch harness connector, test for 8.5-12.8 volts between the signal circuits listed below and ground.
    • Sunroof open terminal 6
    • Sunroof close terminal 4
    • Vent open (Crew Cab) terminal 2
    • Vent close (Crew Cab) terminal 8
    • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof motor/actuator.
  10. If all circuits test normal, replace the sunroof motor/actuator.

Crew Cab Power Sunroof Express Feature Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Ignition ON, with the sunroof in the closed position, connect 3A fused jumper wires between both signal circuits listed below and ground for less than 1 second. The sunroof should express open.
    • Terminal 1
    • Terminal 6
    • If the sunroof did not express open, test the signal circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof motor/actuator.
  3. With the sunroof in the open position, connect 3A fused jumper wires between both signal circuits listed below and ground for less than 1 second. The sunroof should express open.
    • Terminal 1
    • Terminal 4
    • If the sunroof did not express open, test the signal circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof motor/actuator.
  4. If all circuits test normal, replace the sunroof switch.
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