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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Lucerne 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Power Sunroof Inoperative

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

1

1

--

--

Ignition

1

1

--

--

Sunroof Switch Close Signal

1

1

1*

--

Sunroof Switch Close Vent Signal

1

1

1*

--

Sunroof Switch Express Signal

1

2

1*

--

Sunroof Switch Express Vent Signal

1

2

1*

--

Sunroof Switch Open Signal

1

1

1*

--

Sunroof Switch Open Vent Signal

1

1

1*

--

Ground - Sunroof Switch

--

1

--

--

Ground - Sunroof Motor/Actuator

--

1

--

--

* Internal damage to the sunroof switch may occur if shorted to B+

1. Power sunroof malfunction

2. Power sunroof express feature malfunction

Circuit/System Description

The sunroof module determines the sunroof motor direction based on inputs received from the overhead console sunroof switches. The module supplies each of the sunroof switch signal circuits with a 12-volt reference. When the switch is pressed the signal circuit is pulled low signaling the roof open or closed request. When the ignition switch is in the ON position or when retained accessory power (RAP) is active, voltage is applied to the sunroof module via the RAP relay and the S/ROOF fuse. For a description and operation of the RAP system, refer to Retained Accessory Power (RAP) Description and Operation . The sunroof module controls the sunroof motor direction by changing the polarity of the applied voltage. The sunroof module remembers the sunroof position whenever the ignition switch is turned to the OFF position. The limit switch is used as an input to the sunroof module to indicate that the glass is fully closed, or in the soft stop positions. The limit switch is grounded only when the sunroof glass is in the fully closed or soft stop positions, otherwise it is open.

Diagnostic Aids

A short to B+ on any of the sunroof switch signal circuits will open the ground trace in the sunroof switch.

Reference Information

Schematic Reference

Sunroof Schematics

Connector End View Reference

Power Roof Systems Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

Power Sunroof Inoperative

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Interior lamps OFF, Test for less than 10 ohms of resistance between the ground circuit terminal 5 and ground.
    3. ⇒If greater than 10 ohms, test the ground circuit for an open/high resistance.
  3. Connect a 3A fused jumper wire between the signal circuit terminals listed below and ground. The roof should be inoperative in at least one or more directions.
    4. • Terminal 8 sunroof switch open signal
    • Terminal 2 sunroof switch close signal
    • Terminal 4 sunroof switch open vent signal
    • Terminal 6 sunroof switch close vent signal
    ⇒If the roof moved in all directions, replace the sunroof switch.
  4. Disconnect the harness connector at the sunroof motor/actuator assembly.
  5. Test for less than 1 ohms of resistance between the ground circuit terminal 4 and ground.
    6. ⇒If greater than 1 ohms, test the ground circuit for an open/high resistance.
  6. Test for less than 1 ohms of resistance between the ground circuit terminal 13 and ground.
    7. ⇒If greater than 1 ohms, test the ground circuit for an open/high resistance.
  7. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit terminal 1 and ground.
    8. ⇒If the test lamp does not illuminate, test the battery positive voltage circuit for a short to ground or an open/high resistance
  8. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit terminal 2 and ground.
    9. ⇒If the test lamp does not illuminate, test the accessory voltage circuit for a short to ground or an open/high resistance
  9. Ignition OFF, connect the harness connector at the sunroof motor/actuator assembly.
  10. Ignition ON, at the sunroof switch harness connector, test for B+ between the signal circuit terminals listed below and ground.
    11. • Terminal 1 sunroof express vent signal
    • Terminal 2 sunroof switch close signal
    • Terminal 4 sunroof switch open vent signal
    • Terminal 6 sunroof switch close vent signal
    • Terminal 7 sunroof express signal
    • Terminal 8 sunroof switch open signal
    ⇒If less than the specified value, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the sunroof motor/actuator assembly.
  11. Ignition OFF, connect the harness connector at the sunroof switch.
  12. If all circuits test normal, test or replace the sunroof motor/actuator assembly.

Power Sunroof Express Feature Inoperative

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Ignition ON, with the sunroof in the closed position, connect a 3A fused jumper wire between the sunroof switch open signal circuit terminal 8 and the sunroof express signal circuit terminal 7 to ground for less than 1 second. The roof should express open.
    3. ⇒If the roof did not express open, test the express signal circuit for a short to voltage or an open high resistance. If the circuit tests normal, replace the sunroof motor/actuator assembly.
  3. Ignition ON, with the sunroof in the closed position, connect a 3A fused jumper wire between the sunroof switch vent open signal circuit terminal 4 and the sunroof express vent signal circuit terminal 1 to ground for less than 1 second. The roof should express vent open.
    4. ⇒If the roof did not express vent open, test the express signal circuit for a short to voltage or an open high resistance. If the circuit tests normal, replace the sunroof motor/actuator assembly.
  4. 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 following sunroof switch terminals with the switch in the open position:
    3. • Switch low reference terminal 5 and roof open terminal 8
    • Switch low reference terminal 5 and roof express terminal 7
    • Switch low reference terminal 5 and roof close terminal 2
    • Switch low reference terminal 5 and vent open terminal 4
    • Switch low reference terminal 5 and vent express terminal 1
    • Switch low reference terminal 5 and vent close terminal 6
    ⇒If less than infinite for any test, replace the sunroof switch.

    Important: 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.

  3. Test for less than 3 ohms of resistance between the following sunroof switch terminals while pressing the appropriate switch.
    4. • Switch low reference terminal 5 and roof open terminal 8
    • Switch low reference terminal 5 and roof express terminal 7
    • Switch low reference terminal 5 and roof close terminal 2
    • Switch low reference terminal 5 and vent open terminal 4
    • Switch low reference terminal 5 and vent express terminal 1
    • Switch low reference terminal 5 and vent close terminal 6
    ⇒If greater than 3 ohms on any of the tests, replace the sunroof switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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