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

B+

1

1

--

--

Ignition

1

1

2

--

Close Switch Signal

1

1

1

--

Open Switch Signal

1

1

1

--

Ground

--

1

--

--

1. Power sunroof inoperative

2. Power sunroof operates with ignition off

Circuit/System Description

The sunroof module supplies each of the sunroof switch signal circuits with a 12-volt reference. When a switch is pressed the signal circuit is pulled low signaling the sunroof open or close request. The motor determines the motor direction based on inputs received from the sunroof switch. When the motor reverses the polarity of the applied voltage, the motor reverses direction.

Reference Information

Schematic Reference

Sunroof Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Sunroof Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. With the sunroof in the closed position, press the sunroof open switch. The sunroof should open.
  2. With the sunroof in the open position, press the sunroof close switch. The sunroof should close.

Circuit/System Testing

Important: Because of the accessibility of the sunroof switch, perform the sunroof switch component test before beginning the Circuit/System Testing.

  1. Ignition OFF, disconnect the harness connector at the sunroof module .
  2. Test for less than 5.0 ohms between the ground circuit terminal 7 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the fuse and replace the sunroof module.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 8 and ground.
  7. If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. If the circuit tests normal, refer to Retained Accessory Power (RAP) Malfunction .
  8. Ignition OFF, connect the harness connector at the sunroof module.
  9. Disconnect the harness connector at the sunroof switch.
  10. Test for less than 5.0 ohms between the ground circuit terminal C and ground.
  11. If greater than the specified range, test the ground circuit for an open/high resistance.

    Important: Apply ground to the module for no longer than 2 seconds at a time or the module could be damaged.

    When performing the following tests, make sure that the sunroof or sunshade is not at its end of travel position by switching the grounded jumper to the other signal circuit if the sunroof or sunshade does not move in one direction.

  12. Ignition ON, momentarily install a 10-amp fused jumper wire between the signal circuit terminal D and ground. The sunroof should move.
  13. If the sunroof does not move, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof module.
  14. Momentarily install a 10-amp fused jumper wire between the signal circuit terminal E and ground. The sunroof should move.
  15. If the sunroof does not move, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof module.
  16. If all circuits test normal, test or replace the sunroof switch.

Component Testing

Sunroof Switch

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Test for infinite resistance between the switch terminals listed below and the ground circuit terminal C with the switch in the neutral position.
  3. • Sunroof close terminal E
    • Sunroof open terminal D
    If not the specified value, replace the sunroof switch.
  4. Test for less than 5.0 ohms between the switch terminals listed below and the ground circuit terminal C with the switch in the appropriate position.
  5. • Sunroof close terminal E
    • Sunroof open terminal D
    If greater than the specified value, replace the sunroof switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Power Sunroof Motor Replacement
    •  Sunroof Switch Replacement
    •  Control Module References for sunroof module replacement, setup, and programming