GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Power Sunroof System Check ?

--

Go to Step 2

Go to Power Sunroof System Check

2

Check the PWR SUNRF circuit breaker 1 in the IP fuse block by visual inspection.

Is the circuit breaker open?

--

Go to Step 3

Go to Step 4

3

  1. Repair the short to ground in CKT 341 (BRN).
  2. Reset the PWR SUNRF circuit breaker 1 in the IP fuse block.

Is the repair complete?

--

Go to Step 30

--

4

  1. Turn the ignition switch to OFF.
  2. Disconnect the sunroof control module connectors C1 and C2.
  3. Turn the ignition switch to RUN.
  4. Connect a J 39200 digital multimeter (DMM) between the sunroof control module connector C1 terminal C and ground.

Is the measured voltage within the specified range?

10-15V

Go to Step 6

Go to Step 5

5

Repair the open in CKT 341 (BRN).

Is the repair complete?

--

Go to Step 30

--

6

Connect a DMM between the sunroof control module connector C1 terminals C and D.

Is the measured voltage within the specified range?

10-15V

Go to Step 8

Go to Step 7

7

Repair the open in CKT 1450 (BLK).

Is the repair complete?

--

Go to Step 30

--

8

  1. Disconnect the sunroof switch.
  2. Using a DMM, measure the following voltages:
  3. • From battery positive voltage to sunroof control module connector C2 terminal 7.
    • From battery positive voltage to sunroof control module connector C2 terminal 6.

Is either measured voltage within the specified range?

10-15V

Go to Step 9

Go to Step 10

9

Repair the short to ground in CKT 100 (BRN) or CKT 110 (ORN).

Is the repair complete?

--

Go to Step 30

--

10

Using a DMM, measure the following resistances:

    •  Across sunroof control module connector C2 terminals 5 and 6.
    •  Across sunroof control module connector C2 terminals 5 and 7.

Is either measured resistance less than the specified value?

Infinite (OL)

Go to Step 11

Go to Step 12

11

Repair the short from CKT 110 (ORN) or CKT 100 (BRN) to CKT 128 (BLK).

Is the repair complete?

--

Go to Step 30

--

12

  1. Reconnect the sunroof switch.
  2. Connect a DMM set to ohms scale across sunroof control module connector C2 terminals 5 and 6.
  3. Press the sunroof switch to OPEN, then release the switch.

Is the measured resistance less than the specified value with the switch pressed and infinite (OL) with the switch released?

5ohms

Go to Step 13

Go to Step 14

13

  1. Connect a DMM set to ohms scale across sunroof control module connector C2 terminals 5 and 7.
  2. Press the sunroof switch to CLOSE, then release the switch.

Is the measured resistance less than the specified value with the switch pressed and infinite (OL) with the switch released?

5ohms

Go to Step 26

Go to Step 16

14

  1. Disconnect the sunroof switch.
  2. Connect a fused jumper across sunroof switch terminals D and E.
  3. Using a DMM, measure the resistance across sunroof control module terminals 5 and 6.

Is the measured resistance less than the specified value with the jumper installed and infinite (OL) with the jumper removed?

5ohms

Go to Step 18

Go to Step 15

15

Repair the open in CKT 100 (BRN) or CKT 128 (BLK).

Is the repair complete?

--

Go to Step 30

--

16

  1. Disconnect the sunroof switch.
  2. Connect a fused jumper across sunroof switch terminals D and C.
  3. Using a DMM, measure the resistance across sunroof control module terminals 5 and 7.

Is the measured resistance less than the specified value with the jumper installed and infinite (OL) with the jumper removed?

5ohms

Go to Step 18

Go to Step 17

17

Repair the open in CKT 110 (ORN) or CKT 128 (BLK).

Is the repair complete?

--

Go to Step 30

--

18

  1. Inspect the sunroof switch connector for poor terminal contact.
  2. If OK, replace the sunroof switch. Refer to Sunroof Switch Replacement.

Is the repair complete?

--

Go to Step 30

--

19

  1. Open the sunroof using the following method:
  2. 1.1. Partially lower the headliner.
    1.2. Locate the slot in the track transmission.
    1.3. Using a flat-bladed screwdriver, apply upward pressure to release the clutch and manually turn the transmission.
  3. Using a DMM, measure the resistance between the sunroof control module connector C2 terminal 8 and ground.

Is the measured resistance less than the specified value?

Infinite (OL)

Go to Step 20

Go to Step 22

20

Inspect CKT 132 (RED) for a short to ground.

Is the circuit OK?

--

Go to Step 29

Go to Step 21

21

Repair short to ground on CKT 132 (RED).

Is the repair complete?

--

Go to Step 30

--

22

Using a DMM, measure the resistance between the sunroof control module connector C2 terminal 8 and terminal 1.

Is the measured resistance less than the specified value?

Infinite (OL)

Go to Step 25

Go to Step 23

23

Inspect for a short between CKT 132 (RED) and CKT 133 (YEL).

Are the circuits OK?

--

Go to Step 29

Go to Step 24

24

Repair the short between CKT 132 (RED) and CKT 133 (YEL).

Is the repair complete?

--

Go to Step 30

--

25

  1. Close the sunroof.
  2. Connect a fused jumper between the sunroof control module connector C1 terminals C and B.
  3. Connect a fused jumper between the sunroof control module connector C1 terminals A and D.

Does the sunroof motor operate?

--

Go to Step 26

Go to Step 27

26

  1. Inspect the sunroof control module connector C1 for proper terminal contact.
  2. If OK, replace the sunroof control module. Refer to Power Sunroof Express Module Replacement .

Is the repair complete?

--

Go to Step 30

--

27

Inspect CKT 127 (GRN) and CKT 129 (LT GRN) for an open or a short to ground.

Are the circuits OK?

--

Go to Step 29

Go to Step 28

28

Repair the open or short to ground on CKT 127 (GRN) or CKT 129 (LT GRN).

Is the repair complete?

--

Go to Step 30

--

29

  1. Inspect the sunroof actuator terminals for poor terminal contact.
  2. If OK, replace the sunroof actuator. Refer to Power Sunroof Motor Replacement .

Is the repair complete?

--

Go to Step 30

--

30

  1. Make sure any components removed during diagnosis are installed in place and that all connectors are connected.
  2. Repeat the system check. Refer to Power Sunroof System Check .

Is the system check complete?

--

System OK

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