GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Century 🢒 Body and Accessories 🢒 Roof 🢒 Power Sunroof Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Using a jumper wire to simulate operation of the sunroof to determine if the switch is at fault.

    2.

  2. Disconnecting the sunroof limit switch/sunroof opening position switch harness connector and shorting the sunroof limit switch position 1-LS1 circuit, the sunroof module thinks the glass is in the closed position, allowing any request from the sunroof switch to enable an output to the sunroof motor/actuator for testing.

    3.

  3. When the sunroof control module is at rest the sunroof motor/actuator open and close circuits are at ground potential. This step is testing for an output to drive the motor, when the sunroof control module should be idle.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Power Roof Systems Connector End Views

DEFINITION: Sunroof inoperative, does not open, close, or vent and can be inoperative in any position.

1

Did you perform the A Diagnostic System Check - Power Sunroof?

--

Go to Step 2

Go to Diagnostic System Check - Power Sunroof

2

Operate the power sunroof.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3
  1. Turn ON the ignition, with the engine OFF.
  2. Operate the LF window switch?

Does the LF window operate?

--

Go to Step 5

Go to Step 4

4

Operate the radio.

Does the radio operate?

--

Go to Step 30

Go to Retained Accessory Power (RAP) Inoperative in Retained Accessory Power

5

  1. Remove the sunroof switch from the headliner.
  2. Disconnect the sunroof switch from the harness connector.
  3. Observing the position of the sunroof, try to operate the sunroof by connecting a fused jumper between the sunroof switch low reference circuit to either the sunroof switch open signal circuit and or to the sunroof switch close signal circuit.

Does the sunroof operate normally?

--

Go to Step 33

Go to Step 6

6
  1. Remove the jumper wire.
  2. Measure the reference voltage of the sunroof switch open signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 7

Go to Step 17

7

Measure the reference voltage of the sunroof switch close signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 8

Go to Step 21

8

Measure the reference voltage of the sunroof switch close signal circuit and the sunroof switch low reference circuit at the sunroof switch harness connector.

Does the voltage measure near the specified value?

5 V

Go to Step 9

Go to Step 22

9
  1. Disconnect the sunroof opening position switch harness connector.
  2. Measure the reference voltage of the sunroof limit switch position 1-LS1 circuit at the sunroof opening position switch harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 10

Go to Step 23

10

Measure the reference voltage of the sunroof limit switch position 2-LS2 circuit at the sunroof opening position switch harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 11

Go to Step 24

11

Measure the reference voltage of the sunroof limit switch position 3-LS3 circuit at the sunroof opening position switch harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 12

Go to Step 25

12

Measure the reference voltage between the sunroof limit switch position 3-LS3 circuit and the sunroof limit switch low reference circuit at the sunroof opening position switch harness connector.

Does the voltage measure near the specified value?

5 V

Go to Step 13

Go to Step 26

13

  1. Reconnect the sunroof switch to the harness connector.
  2. Connect a jumper between the sunroof limit switch position 1-LS1 circuit and the sunroof limit switch low reference circuit at the sunroof opening position switch harness connector.
  3. Observing the position of the sunroof glass, operate the system by pressing the sunroof switch to slide the sunroof glass to the available positions not exceeding the full vent or full open positions.

Does the sunroof glass slide as requested?

--

Go to Step 35

Go to Step 14

14

  1. Wait 15 seconds.
  2. Disconnect the sunroof motor/actuator harness connector.
  3. Connect a test lamp between the sunroof motor/actuator open control and motor close control circuits at the sunroof motor harness connector.

Does the test lamp illuminate?

--

Go to Step 44

Go to Step 15

15
  1. Leave the test lamp between the sunroof motor/actuator control circuits, as in previous step.
  2. Press and hold the sunroof switch to the open position for 3 seconds.

Did the test lamp illuminate?

--

Go to Step 16

Go to Step 27

16
  1. Leave the test lamp between the sunroof motor/actuator control circuits, as in previous step.
  2. Press and hold the sunroof switch to the close position for 3 seconds.

Did the test lamp illuminate?

--

Go to Step 34

Go to Step 44

17

Measure the reference voltage of the sunroof switch close signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

5V

Go to Step 18

Go to Step 19

18

Test the sunroof switch open signal circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

19
  1. Disconnect the sunroof control module harness connector that contains the sunroof accessory voltage circuit.
  2. Measure the sunroof accessory voltage circuit at the sunroof control module harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 20

Go to Step 37

20

Measure the voltage between the sunroof accessory voltage circuit and the sunroof ground circuit at the sunroof control module harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 36

Go to Step 38

21

Test the sunroof switch close signal circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

22

Test the sunroof switch low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

23

Test the sunroof limit switch position 1-LS1 circuit for an open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

24

Test the sunroof limit switch position 2-LS2 circuit for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

25

Test the sunroof limit switch position 3-LS3 circuit for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

26

Test the sunroof limit switch low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

27
  1. Connect the test lamp between the sunroof motor open control circuit at the module side of the sunroof motor/actuator harness connector, and a good ground.
  2. Press and hold the sunroof switch to the open position for 3 seconds.

Did the test lamp illuminate?

--

Go to Step  29

Go to Step  28

28

Test the sunroof motor open control circuit for an open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

29

Test the sunroof motor close control circuit for an open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 36

30
  1. Remove the Pwr Windows Pwr Sunroof circuit breaker.
  2. Measure the voltage between the RAP relay switch supply voltage circuit at the circuit breaker and a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 31

Go to Step 39

31

Test the accessory voltage circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 32

32

Inspect the Pwr Windows Pwr Sunroof circuit breaker for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 40

33

Inspect for poor connections at the sunroof switch and harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 41

34

Inspect for poor connections at the sunroof motor/actuator harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 42

35

Inspect for poor connections at the sunroof opening position switch and harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 43

36

Inspect for poor connections at the sunroof control module and harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 44

37

Repair an open or high resistance in the sunroof accessory voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

--

38

Repair an open in the sunroof ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

--

39

Repair an open in the RAP relay switch supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

--

40

Replace the circuit breaker.

Did you complete the repair?

--

Go to Step 45

--

41

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Did you complete the repair?

--

Go to Step 45

--

42

Replace the sunroof motor/actuator. Refer to Sunroof Motor/Actuator Replacement .

Did you complete the repair?

--

Go to Step 45

--

43

Replace the sunroof opening position switch. Refer to Sunroof Opening Position Switch Replacement .

Did you complete the repair?

--

Go to Step 45

--

44

Replace sunroof control module. Refer to Sunroof Control Module Replacement .

Did you complete the repair?

--

Go to Step 45

--

45
  1. Remove any jumper wires.
  2. Reconnect any connectors.
  3. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3