GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the power sunroof system check performed?

--

Go to Step 2

Go to Power Sunroof System Check

2

  1. Turn the ignition switch on.
  2. Operate the LF power window.

Does the LF power window operate?

--

Go to Step 8

Go to Step 6

3

  1. Remove the sunroof switch from the headliner and leave the sunroof switch harness connector connected.
  2. Using a DMM, measure the voltage by backprobing between the sunroof switch connector terminal B and ground.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 4

Go to Step 19

4

Using a DMM, measure the voltage by backprobing between the sunroof switch harness connector terminal C and ground.

Is the voltage measured within the specified range?

(Note: if the DMM displays B+, then go to step 39).

4.5-5.5V

Go to Step 5

Go to Step 23

5

Using a DMM, measure the voltage by backprobing between the sunroof switch harness connector terminals B and F.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 10

Go to Step 26

6

Check the PWR WINDOWS PWR SUNROOF circuit breaker located in the fuse block.

Is the PWR WINDOWS PWR SUNROOF circuit breaker open?

--

Go to Step 7

Go to Step 8

7

Repair short to ground in circuit 143.

Is the repair complete?

--

Go to Power Sunroof System Check

--

8

Using a test light, connect by backprobing between C398 terminal A and ground.

Is the test light on?

--

Go to Step 9

Go to Step 28

9

  1. Turn the ignition switch off.
  2. Disconnect the sunroof module electrical connector C2.
  3. Turn the ignition switch on.
  4. Using a test light and a J 35616A kit, connect between the sunroof module harness connector C2 terminals B and D.

Is the test light on?

--

Go to Step 3

Go to Step 29

10

  1. Connect a test light by backprobing between the sunroof module harness connector C2 terminal A and ground.
  2. While observing the test light, press and hold close on the sunroof switch.

Is the test light on?

--

Go to Step 11

Go to Step 22

11

  1. Connect a test light by backprobing between the sunroof module harness connector C2 terminal C and ground.
  2. While observing the test light, press and hold open on the sunroof switch.

Is the test light on?

--

Go to Step 14

Go to Step 22

12

  1. Turn the ignition switch off.
  2. Disconnect the sunroof actuator connector C3.
  3. Connect a test light between the sunroof actuator harness connector C3 terminals 1 and 2.
  4. While observing the test light, press and hold close on the sunroof switch.

Is the test light on?

--

Go to Step 13

Go to Step 30

13

  1. Leave the test light connected (from previous step).
  2. While observing the test light, press and hold open on the sunroof switch.

Is the test light on?

--

Go to Step 18

Go to Step 30

14

  1. Turn the ignition switch off.
  2. Reconnect the sunroof module.
  3. Turn the ignition switch on.
  4. Using a DMM, measure the voltage by backprobing between the limit switch module harness connector C4 terminal 1 and ground.

Is the voltage measured within the specified range? (Note: if voltage measured is B+, then go to step 39).

4.5-5.5V

Go to Step 15

Go to Step 31

15

Using a DMM, measure the voltage by backprobing between the limit switch module harness connector C4 terminal 3 and ground.

Is the voltage measured within the specified range? (Note: if voltage measured is B+, then go to step 39).

4.5-5.5V

Go to Step 16

Go to Step 34

16

Using a DMM, measure the voltage by backprobing between the limit switch module harness connector C4 terminal 4 and ground.

Is the voltage measured within the specified range? (Note: if voltage measured is B+, then go to step 39).

4.5-5.5V

Go to Step 17

Go to Step 36

17

Using a DMM, measure the voltage by backprobing between the limit switch module harness connector C4 terminals 2 and 4.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 12

Go to Step 38

18

Replace the sunroof actuator. Refer to Power Sunroof Motor Replacement .

Is the repair complete?

--

Go to Power Sunroof System Check

--

19

  1. Disconnect the sunroof switch electrical connector.
  2. Using a DMM and a J 35616A kit, measure the voltage between the sunroof switch harness connector terminal B and ground.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 21

Go to Step 20

20

Locate open or short to ground in circuit 100.

Is there an open or short to ground in circuit 100?

--

Go to Step 40

Go to Step 22

21

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Is the repair complete?

--

Go to Power Sunroof System Check

--

22

Replace the sunroof module. Refer to Power Sunroof Express Module Replacement .

Is the repair complete?

--

Go to Power Sunroof System Check

--

23

  1. Disconnect the sunroof switch electrical connector.
  2. Using a DMM and a J 35616A kit, measure the voltage between the sunroof switch harness connector terminal C and ground.

Is the measured voltage within the specified value?

4.5-5.5V

Go to Step 21

Go to Step 24

24

Repair open or short to ground in circuit 110.

Is the repair complete?

--

Go to Power Sunroof System Check

--

25

Repair the open or short to ground.

Is the repair complete?

--

Go to Power Sunroof System Check

--

26

  1. Turn the ignition switch off.
  2. Disconnect the sunroof switch electrical connector.
  3. Disconnect the sunroof module electrical connector C1.
  4. Using a DMM, measure the resistance between the sunroof switch harness connector terminal F and the sunroof module harness connector C1 terminal 3.

Is the measured resistance within the specified range?

Less than 2ohms

Go to Step 22

Go to Step 27

27

Repair poor connection or open in circuit 128.

Is the repair complete?

--

Go to Power Sunroof System Check

--

28

Repair poor connection or open in circuit 143.

Is the repair complete?

--

Go to Power Sunroof System Check

--

29

Repair poor connection or open in circuit 850.

Is the repair complete?

--

Go to Power Sunroof System Check

--

30

Repair poor connection or open in circuit 127 or circuit 129.

Is the repair complete?

--

Go to Power Sunroof System Check

--

31

  1. Disconnect the limit switch module electrical connector C4.
  2. Using a DMM and a J 35616A kit, measure the voltage between the limit switch module harness connector C4 terminal 1 and ground.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 33

Go to Step 32

32

Locate open or short to ground in the BLK wire between the sunroof module harness connector C1 terminal 6 and the limit switch module harness connector C4 terminal 1.

Is there an open or short to ground in the BLK wire?

--

Go to Step 41

Go to Step 22

33

Replace the limit switch module.

Is the repair complete?

--

Go to Power Sunroof System Check

--

34

  1. Disconnect the limit switch module harness connector C4.
  2. Using a DMM and a J 35616A kit, measure the voltage between the limit switch module harness connector C4 terminal 3 and ground.

Is the voltage measured within the specified range?

4.5-5.5V

Go to Step 33

Go to Step 35

35

Locate open or short to ground in WHT wire between the sunroof module harness connector C1 terminal 8 and the limit switch module harness connector C4 terminal 3.

Is there an open or short to ground in the WHT wire?

--

Go to Step 42

Go to Step 22

36

  1. Disconnect the limit switch module harness connector C4.
  2. Using a DMM and a J 35616A kit, measure the voltage between the limit switch module harness connector C4 terminal 4 and ground.

Is the voltage measured within the specified range?

5.5-6.5V

Go to Step 33

Go to Step 37

37

Locate open or short to ground in the RED wire between the sunroof module harness connector C1 terminal 7 and the limit switch module harness connector C4 terminal 4.

Is there an open or short to ground in the RED wire?

--

Go to Step 43

Go to Step 22

38

Locate open in the BLK/WHT wire between the sunroof module harness connector C1 terminal 1 and the limit switch module harness connector C4 terminal 2.

Is there an open in the BLK/WHT wire?

--

Go to Step 44

Go to Step 22

39

Repair the short to B+.

Is the repair complete?

--

Go to Power Sunroof System Check

--

40

Repair the open or short to ground in circuit 100.

Is the repair complete?

--

Go to Power Sunroof System Check

--

41

Repair open or short to ground in the BLK wire between the sunroof module harness connector C1 terminal 6 and the limit switch module harness connector C4 terminal 1.

Is the repair complete?

--

Go to Power Sunroof System Check

--

42

Repair open or short to ground in the WHT wire between the sunroof module harness connector C1 terminal 8 and the limit switch module harness connector C4 terminal 3.

Is the repair complete?

--

Go to Power Sunroof System Check

--

43

Repair open or short to ground in the RED wire between the sunroof module harness connector C1 terminal 7 and the limit switch module harness connector C4 terminal 4.

Is the repair complete?

--

Go to Power Sunroof System Check

--

44

Repair open in the BLK/WHT wire between the sunroof module harness connector C1 terminal 1 and the limit switch module harness connector C4 terminal 2.

Is the repair complete?

--

Go to Power Sunroof System Check

--