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, 3

1, 3

--

--

Ignition

1, 3

1, 3

--

--

Serial Data

3

3

3

--

Signal Antenna Present

--

5

--

--

Sunroof Switch Close

1, 3

1

1, 3

--

Sunroof Switch Express

1, 3

2

1, 3

--

Sunroof Switch Open

1, 3

1

1, 3

--

Sunshade Switch Close

1, 3

3

1, 3

--

Sunshade Switch Express

1, 3

4

1, 3

--

Sunshade Switch Open

1, 3

3

1, 3

--

Sunroof Switch Ground

--

1, 3

--

--

Sunroof Control Module Ground

--

1, 3

--

--

Sunshade Control Module Ground

--

3

--

--

1. Power Sunroof Inoperative

2. Power Sunroof Express Open/Close Features Inoperative

3. Power Sunshade Inoperative

4. Power Sunshade Express Open/Close Features Inoperative

5. Sunroof Opens Too Far

Circuit/System Description

The sunroof control module supplies voltage to the sunroof switch through the sunroof switch open and close signal circuits. When the roof open or close switch is pressed, ground is applied through the switch contacts and the appropriate signal circuit to the sunroof control module. The sunroof control module then internally applies battery voltage and ground to the appropriate circuits of the reversible sunroof motor in order to move the roof glass panel to the open or closed positions.

The sunshade control module contains the logic for opening and closing the sunshade based on serial data from the sunroof switch through the sunroof control module. The sunshade control module internally applies battery voltage and ground to the appropriate circuits of the reversible sunshade motor in order to move the sunshade panel to the open or closed positions.

Diagnostic Aids

If the sunroof and/or sunshade are experiencing an intermittent inoperative condition, check the sunroof switch ground circuit for an open condition. If the sunroof switch ground circuit is open, the switch may take a redundant path to ground through the illumination circuit. When the lights are turned ON, the redundant path is removed, and the sunroof and/or sunshade will become inoperative.

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

Circuit/System Verification

  1. With the sunroof in the closed position, press the sunroof open switch. The sunroof should open.
  2. If the sunroof does not open, refer to Power Sunroof Malfunction.
  3. With the sunroof in the open position, press the sunroof close switch. The sunroof should close.
  4. If the sunroof does not close, refer to Power Sunroof Malfunction.
  5. With the sunroof in the closed position, operate the sunroof express open feature. The sunroof should fully open.
  6. If the express open feature does not function, refer to Power Sunroof Express Feature Malfunction.
  7. With the sunroof fully open, the sunroof should not contact the XM antenna or coax cable.
  8. If the sunroof contacts the XM antenna or coax cable, refer to Sunroof Opens Too Far.
  9. With the sunshade in the closed position, press the sunshade open switch. The sunshade should open.
  10. If the sunshade does not open, refer to Power Sunshade Malfunction.
  11. With the sunshade in the open position, press the sunshade close switch. The sunshade should close.
  12. If the sunshade does not close, refer to Power Sunshade Malfunction.
  13. With the sunshade in the closed position, operate the sunshade express open feature. The sunshade should fully open.
  14. If the express open feature does not function, refer to Power Sunshade Express Feature Malfunction.

Circuit/System Testing

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

Power Sunroof Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof control module.
  2. Test for less than 5.0 Ω between the ground circuit terminal 2 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 4 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, determine if the sunroof control module or the sunshade control module is causing the fuse to open. Replace the appropriate module.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 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 Malfunction.
  8. Ignition OFF, connect the harness connector at the sunroof control module.
  9. Disconnect the harness connector at the sunroof switch.
  10. Test for less than 5.0 Ω between the ground circuit terminal 5 and ground.
  11. If greater than the specified range, test the ground circuit for an open/high resistance.

    Note: 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 A fused jumper wire between the signal circuit terminal 8 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 control module.
  14. Momentarily install a 10 A fused jumper wire between the signal circuit terminal 2 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 control module.
  16. If all circuits test normal, test or replace the sunroof switch.

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, install 3 A fused jumper wires between both signal circuits listed below and ground for less than 1 second. The roof should express open.
  3. • Terminal 7
    • Terminal 8
    If the roof does not express open, test the signal circuit terminal 7 for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof control module.
  4. If all circuits test normal, replace the sunroof switch.

Sunroof Opens Too Far

  1. Ignition OFF, disconnect the harness connector at the sunroof control module.
  2. Test for less than 5.0 Ω between the ground circuit terminal 3 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. If all circuit test normal, replace the sunroof control module.

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

Power Sunshade Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof sunshade module.
  2. Test for less than 5.0 Ω between the ground circuit terminal 9 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, determine if the sunroof control module or the sunshade control module is causing the fuse to open. Replace the appropriate module.
  6. Ignition ON, test for 10 - 40 Hz between the serial data circuit terminal 1 and ground.
  7. If less than the specified range, test the serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof control module.
  8. Test for 50 - 200 Hz between the serial data circuit terminal 1 and ground while operating the sunshade switch in the forward and rearward directions.
  9. If not the specified range, replace the sunroof control module.
  10. Ignition OFF, connect the harness connector at the sunshade control module.
  11. Disconnect the harness connector at the sunroof switch.
  12. Test for less than 5.0 Ω between the ground circuit terminal 5 and ground.
  13. If greater than the specified range, test the ground circuit for an open/high resistance.

    Note: 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.

  14. Ignition ON, momentarily install a 10 A fused jumper wire between the signal circuit terminal 4 and ground. The sunshade should move.
  15. If the sunshade 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 sunshade control module.
  16. Momentarily install a 10 A fused jumper wire between the signal circuit terminal 6 and ground. The sunshade should move.
  17. If the sunshade 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 sunshade control module.
  18. If all circuits test normal, test or replace the sunroof switch.

Power Sunshade Express Feature Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Ignition ON, with the sunshade in the closed position, install 3 A fused jumper wires between both signal circuits listed below and ground for less than 1 second. The sunshade should express open.
  3. • Terminal 1
    • Terminal 4
    If the sunshade does 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 control module.
  4. If all circuits test normal, replace the sunroof switch.

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

Component Testing

Sunroof/Sunshade 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 5 with the switch in the neutral position.
  3. • Shade express terminal 1
    • Roof close terminal 2
    • Shade open terminal 4
    • Shade close terminal 6
    • Roof express terminal 7
    • Roof open terminal 8
    If not the specified value, replace the sunroof switch.

    Note: If the switch tests open in any switch position other than Off, test the sunroof switch signal circuits for a short to voltage before replacing the switch.

  4. Test for less than 5 Ω between the switch terminals listed below and the ground circuit terminal 5 with the switch in the appropriate position.
  5. • Shade express terminal 1
    • Roof close terminal 2
    • Shade open terminal 4
    • Shade close terminal 6
    • Roof express terminal 7
    • Roof open terminal 8
    If greater than the specified range, replace the sunroof switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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