GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Positive Voltage

1

1

--

--

Accessory Voltage

1

1

--

--

Sunroof Switch Close Signal

3

3

1

--

Sunroof Switch Open Signal

1

2

1

--

Sunroof Switch Low Reference

--

1

--

--

Sunroof Motor Ground

--

1

--

--

1. Power sunroof inoperative

2. Power sunroof does not open

3. Power sunroof does not close

Circuit/System Description

The sunroof motor/actuator is located between the headliner and the roof structure, while the sunroof switch is located above the rearview mirror. The sunroof motor/actuator supplies voltage to the sunroof switch through the sunroof switch open and close signal circuits. It also supplies ground to the sunroof switch through the switch low reference circuit. When the roof open or closed switch is pressed, ground is applied through the switch contacts and the appropriate signal circuit to the motor/actuator. The motor/actuator then internally applies battery positive voltage and ground to the appropriate circuits of the reversible power sunroof motor in order to move the sunroof glass panel to the open, close, or vent position.

Diagnostic Aids

    • Because of the accessibility of the sunroof switch, perform the sunroof switch component test before beginning the circuit/system testing.
    • A short to B+ on one of the sunroof switch signal circuits will open the switch. This fault is not covered in the circuit/system testing.

Reference Information

Schematic Reference

Sunroof Schematics

Connector End View Reference

Sunroof Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Test for less than 5.0 ohms of resistance between the low reference circuit terminal B and ground.
  3. If greater than the specified range, test the following ground circuits for an open/high resistance. If the circuits test normal, replace the sunroof motor/actuator.
    • Sunroof switch low reference circuit terminal B
    • Sunroof motor/actuator harness connector ground circuit terminal 1
  4. Connect a 3A fused jumper wire between the following sunroof switch signal circuits and ground. The roof should be inoperative in at least one or more directions.
  5. • Terminal D sunroof switch open signal
    • Terminal E sunroof switch close signal
    If the roof moved in all directions, replace the sunroof switch.
  6. Ignition OFF, disconnect the harness connector at the sunroof motor/actuator.
  7. Test for less than 5.0 ohms of resistance between the ground circuit terminal 1 and ground.
  8. If greater than the specified range, test the ground circuit for an open/high resistance.
  9. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.
  10. If the test lamp does not illuminate, repair the B+ circuit for a short to ground or an open/high resistance.
  11. Verify that a test lamp illuminates between the accessory voltage circuit terminal 3 and ground.
  12. If the test lamp does not illuminate, repair the accessory voltage circuit for a short to ground or an open/high resistance.
  13. Ignition OFF, connect the sunroof motor/actuator harness connector.
  14. Disconnect the harness connector at the sunroof switch.
  15. Ignition ON, test for B+ between the sunroof switch signal circuits listed below and ground.
  16. • Sunroof switch open signal terminal D
    • Sunroof switch close signal terminal E
    If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the motor/actuator.
  17. If all circuit test normal, replace the sunroof motor/actuator.

Component Testing

Sunroof Switch

  1. With the ignition OFF, disconnect the sunroof switch harness connector.
  2. Test for infinite resistance between the sunroof switch open signal terminal D and the ground circuit terminal B.
  3. If less than infinite ohms of resistance, replace the sunroof switch.
  4. Test for less than 5.0 ohms of resistance between the sunroof switch open signal terminal D and the ground circuit terminal B while pressing the sunroof open switch.
  5. If greater than 5.0 ohms of resistance, replace the sunroof switch.
  6. Test for infinite resistance between the sunroof switch closed signal terminal E and the ground circuit terminal B.
  7. If less than infinite ohms of resistance, replace the sunroof switch.
  8. Test for less than 5.0 ohms of resistance between the sunroof switch closed signal terminal D and the ground circuit terminal B while pressing the sunroof close switch.
  9. If greater than 5.0 ohms of resistance, replace the sunroof switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Sunroof Switch Replacement
    •  Control Module References for sunroof motor/actuator replacement, setup, and programming