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

Ignition

1

1

--

--

Sunroof Motor Open Control

2

2

3

--

Sunroof Motor Close Control

3

3

2

--

Sunroof Switch Ground

--

1

--

--

1. Power sunroof malfunction

2. Sunroof will not open

3. Sunroof will not close

Circuit/System Description

The power sunroof is controlled by the sunroof switch through the open and close motor control circuits. Ignition voltage is supplied to the sunroof switch through the retained accessory power (RAP) relay and the S/ROOF 20A fuse . While the sunroof switch is in an inactive state both switch contacts are closed to the sunroof switch ground circuit. When an open or close button is pressed on the sunroof switch, its switch contact is closed to the voltage supply circuit. The motor is bi-directional and the direction of motor rotation is determined by which of the motor control circuits is switched to positive voltage while the other remains grounded.

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 vent.
  2. With the sunroof in the closed position, press and hold the sunroof open switch. The sunroof should open.
  3. With the sunroof in the open position, press the sunroof close switch. The sunroof should close.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 1 and ground.
  5. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If circuit tests normal, refer to Retained Accessory Power (RAP) Malfunction .
  6. Ignition OFF, connect the harness connector at the sunroof switch.
  7. Disconnect the harness connector at the sunroof motor.
  8. Connect a test lamp between the control circuit terminal 1 and the control circuit terminal 2.
  9. Ignition ON, command the sunroof from OPEN to CLOSE by pressing the sunroof switch OPEN and CLOSE button. The test lamp should illuminate when switching between the commanded states.
  10. If the test lamp remains OFF during either commanded state, test both control circuits for a short to ground or an open/high resistance. If both circuits test normal, replace the sunroof switch.
  11. If all circuits test normal, test or replace the sunroof motor.

Component Testing

Sunroof Switch

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Test for infinite resistance between the each control circuit and B+ circuit terminal 1.
  3. If less than the specified range, replace the sunroof switch.
  4. While holding the sunroof switch OPEN button, test for less than 1 ohms between the open control circuit terminal and the B+ circuit terminal 1.
  5. If greater than the specified range, replace the sunroof switch.
  6. While holding the sunroof switch CLOSE button, test for less than 1 ohms between the close control circuit terminal and the B+ circuit terminal 1.
  7. If greater than the specified range, replace the sunroof switch.

Sunroof Motor

  1. Ignition OFF, disconnect the harness connector at the sunroof motor.
  2. Install a 20-amp fused jumper wire between the control terminal 1 and 12 volts. Momentarily install a jumper wire between the control terminal 2 and ground. The window motor should OPEN or CLOSE.
  3. If the function does not perform as specified, replace the sunroof motor.
  4. Reverse the jumper wires: The sunroof motor should go in the opposite direction as step 2.
  5. If the function does not perform as specified, replace the sunroof motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.