GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Inspect the sunroof fuse.

Is the fuse open?

--

Go to Step 2

Go to Step 3

2

Repair the short to ground in CKT 541.

Is the repair complete?

--

System OK

--

3

Use a test lamp in order to backprobe the sunroof module harness connector C2 terminal B to ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 4

4

  1. Repair a poor connection or an open in CKT 541.
  2. Retest the system.

Is the repair complete?

--

System OK

--

5

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof switch.
  3. Turn the ignition switch to RUN.
  4. Use a J 39200 digital multimeter (DMM) in order to measure the voltage by backprobing between B+ and the sunroof switch harness connector C4 terminal G.

Is the voltage level within the specified range?

9-14V

Go to Step 6

Go to Step 7

6

  1. Turn the ignition switch to LOCK.
  2. Reconnect the sunroof switch.
  3. Turn the ignition switch to RUN.
  4. Use a J 39200 DMM in order to measure the voltage by backprobing between B+ and the sunroof switch harness connector C4 terminal H.

Is the voltage level within the specified range?

9-14V

Go to Step 8

Go to Step 9

7

Use a J 39200 DMM in order to measure the voltage by backprobing between B+ and the sunroof module connector C1 terminal 5.

Is the voltage level within the specified range?

9-14V

Go to Step 10

Go to Step 11

8

  1. Use a J 39200 DMM in order to measure the voltage by backprobing between B+ and the sunroof switch harness connector terminal F.
  2. Press the sunroof switch CLOSED.

Is the voltage level within the specified range?

9-14V

Go to Step 12

Go to Step 9

9

  1. Replace the sunroof switch. Refer to Sunroof Switch Replacement in Roof.
  2. Retest the system.

Is the repair complete?

--

System OK

--

10

  1. Repair a poor connection or an open in CKT 128.
  2. Retest the system.

Is the repair complete?

--

System OK

--

11

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof module connector C2.
  3. Use a J 39200 DMM in order to backprobe between B+ and the sunroof module harness connector C2 terminal D.

Is the voltage level within the specified range?

9-14V

Go to Step 13

Go to Step 14

12

Use a J 39200 DMM in order to measure the voltage by backprobing between the sunroof switch harness connector C4 terminal H and ground.

Does the voltage equal the specified value?

5V

Go to Step 15

Go to Step 16

13

  1. Replace the sunroof module. Refer to Power Sunroof Module Replacement in Roof.
  2. Retest the system.

Is the repair complete?

--

System OK

--

14

  1. Repair a poor connection or an open in CKT 650 between the sunroof module harness connector C2 terminal D and G302.
  2. Retest the system.

Is the repair complete?

--

System OK

--

15

Use a J 39200 DMM in order to measure the voltage by backprobing between the sunroof switch harness connector C4 terminal F and ground.

Does the voltage equal the specified value?

5V

Go to Step 17

Go to Step 18

16

Use a J 39200 DMM in order to backprobe between the sunroof module harness connector C1 terminal 6 and ground.

Does the voltage equal the specified value?

5V

Go to Step 22

Go to Step 21

17

  1. Turn the ignition switch to LOCK.
  2. Reconnect the sunroof switch.
  3. Disconnect the sunroof actuator connector C3.
  4. Turn the ignition switch to RUN.
  5. Use a J 39200 DMM in order to backprobe between the sunroof actuator harness connector C3 terminals A and B
  6. Press the sunroof switch OPEN and then CLOSED.

Are the voltage levels within the specified range?

9-14V

Go to Step 19

Go to Step 30

18

Use a J 39200 DMM in order to measure voltage by backprobing between the sunroof module harness connector C1 terminal 7 and ground.

Does the voltage equal the specified value?

5V

Go to Step 20

Go to Step 28

19

  1. Replace the sunroof actuator. Refer to Sunroof Actuator Replacement in Roof.
  2. Retest the system.

Is the repair complete?

--

System OK

--

20

  1. Repair a poor connection or an open in CKT 110.
  2. Retest the system.

Is the repair complete?

--

System OK

--

21

  1. Repair a poor connection or an open in CKT 100.
  2. Retest the system.

Is the repair complete?

--

System OK

--

22

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof module connector C1.
  3. Use a J 39200 DMM in order to measure the voltage by backprobing between B+ and the sunroof module harness connector C1 terminal 6.

Is voltage present?

--

Go to Step 23

--

23

  1. Repair a short to ground in CKT 100.
  2. Retest the system.

Is the repair complete?

--

System OK

--

24

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof module connector C2.
  3. Turn the ignition switch to RUN.
  4. Use a J 39200 DMM in order to measure the voltage by backprobing between the sunroof module connector C2 terminal B and terminal D.

Is the voltage level within the specified range?

9-14V

Go to Step 13

Go to Step 25

25

Use a J 39200 DMM in order to measure voltage by backprobing between the sunroof module harness connector C2 terminal B and ground.

Is the voltage level within the specified range?

9-14V

Go to Step 26

Go to Step 27

26

  1. Repair a poor connection or an open in CKT 650 between the sunroof module connector C2 terminal D and G 302.
  2. Retest the system.

Is the repair complete?

--

System OK

--

27

  1. Repair a poor connection or an open in CKT 541.
  2. Retest the system.

Is the repair complete?

--

System OK

--

28

Use a J 39200 DMM in order to measure voltage by backprobing between B+ and the sunroof module harness connector C1 terminal 7.

Is the voltage level within the specified range?

9-14V

Go to Step 29

Go to Step 24

29

  1. Repair a short to ground in CKT 110.
  2. Retest the system.

Is the repair complete?

--

System OK

--

30

  1. Turn the ignition to LOCK.
  2. Disconnect the sunroof module connector C2.
  3. Use a J 39200 DMM in order to measure the voltage by backprobing between the sunroof actuator connector C3 terminal A and ground.

Is voltage present?

--

Go to Step 31

Go to Step 32

31

  1. Repair a short to B+ in CKT 127.
  2. Retest the system.

Is the repair complete?

--

System OK

--

32

Use a J 39200 DMM in order to measure the voltage between B+ and the sunroof actuator harness connector C3 terminal A

Is voltage present?

--

Go to Step 33

Go to Step 34

33

  1. Repair a short to ground in CKT 127.
  2. Retest the system.

Is the repair complete?

--

System OK

--

34

Use a J 39200 DMM in order to test the continuity in CKT 127 between the sunroof module harness connector C2 terminal C and the sunroof actuator connector C3 terminal A.

Is there continuity in CKT 127?

--

Go to Step 35

Go to Step 36

35

Use a J 39200 DMM in order to measure the voltage between the sunroof actuator harness connector C3 terminal B and ground.

Is there voltage?

--

Go to Step 37

Go to Step 38

36

  1. Repair a poor connection or an open in CKT 127.
  2. Retest the system?

Is the repair complete?

--

System OK

--

37

  1. Repair a short to B+ in CKT 129.
  2. Retest the system.

Is the repair complete?

--

System OK

--

38

Use a J 39200 DMM in order to measure the voltage between B+ and the sunroof actuator harness connector C3 terminal B.

Is voltage present?

--

Go to Step 39

Go to Step 40

39

  1. Repair a short to ground in CKT 129.
  2. Retest the system.

Is the repair complete?

--

System OK

--

40

Use a J 39200 DMM in order to test the continuity in CKT 129 between the sunroof module connector C2 terminal A and the sunroof actuator harness connector C3 terminal B.

Is there continuity in CKT 129?

--

Go to Step 41

Go to Step 42

41

  1. Turn the ignition to LOCK.
  2. Reconnect the sunroof module connector C2.
  3. Turn the ignition switch to RUN.
  4. Use a J 39200 DMM in order to backprobe between the sunroof module harness connector C1 terminal 8 and ground.

Is the voltage level within the specified range?

5V

Go to Step 44

Go to Step 43

42

  1. Repair a poor connection or an open in CKT 129.
  2. Retest the system.

Is the repair complete?

--

System OK

--

43

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof module connector C1.
  3. Disconnect the sunroof actuator connector C4.
  4. Use a J 39200 DMM in order to test the continuity to ground in the RED wire.

Is there continuity to ground in the RED wire?

--

Go to Step 53

Go to Step 54

44

Use a J 39200 DMM in order to backprobe between the sunroof module harness connector C1 terminal 2 and ground.

Does the voltage equal the specified value?

5V

Go to Step 45

Go to Step 13

45

Use a J 39200 DMM in order to backprobe between B+ and the sunroof actuator connector C4 terminal A.

Is the voltage level within the specified range?

9-14V

Go to Step 46

Go to Step 47

46

  1. Turn the ignition switch to LOCK.
  2. Disconnect the sunroof module connector C1.
  3. Use a J 39200 DMM in order to backprobe between the sunroof module harness connector C1 terminal 2 and ground.

Is voltage present?

--

Go to Step 48

Go to Step 49

47

Use a J 39200 DMM in order to backprobe between B+ and the sunroof actuator harness connector C5 and terminal C.

Is the voltage within the specified range?

9-14V

Go to Step 19

Go to Step 50

48

  1. Repair a short to B+ in the YEL wire.
  2. Retest the system.

Is the repair complete?

--

System OK

--

49

  1. Repair a poor connection or an open in the YEL wire.
  2. Retest the system.

Is the repair complete?

--

System OK

--

50

Use a J 39200 DMM in order to backprobe between B+ and the sunroof actuator harness connector C4 terminal B.

Is the voltage level within the specified range?

9-14V

Go to Step 51

Go to Step 52

51

  1. Repair a poor connection or an open in the DK BLU wire between S399 and the sunroof actuator connector C5 terminal C.
  2. Retest the system.

Is the repair complete?

--

System OK

--

52

Use a J 39200 DMM in order to backprobe between B+ and the sunroof module connector C1 terminal 1.

Is the voltage level within the specified range?

9-14V

Go to Step 55

Go to Step 13

53

  1. Repair a short to ground in the RED wire.
  2. Retest the system.

Is the repair complete?

--

System OK

--

54

  1. Repair a poor connection or an open in the DK BLU wire between the sunroof module connector C1 terminal 1 and S399.
  2. Retest the system.

Is the repair complete?

--

System OK

--

55

  1. Reconnect the sunroof module connector C1.
  2. Turn the ignition switch to RUN.
  3. Use a J 39200 DMM in order to measure the voltage between the sunroof actuator connector C4 terminal C and ground.

Is the voltage level within the specified range?

5V

Go to Step 19

Go to Step 13