GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Inspect fuse F8.

Is either fuse open?

--

Go to Step 2

Go to Step 3

2

  1. Inspect for a short circuit and repair it, if necessary.
  2. Replace the open fuse.

Did you complete the repair?

--

System OK

--

3

  1. Turn the ignition ON.
  2. Test the voltages at fuse F8.

Are both voltages within the specified range?

11-14 V

Go to Step 5

Go to Step 4

4

Repair the power supply to the fuse which did not indicate battery voltage with the ignition ON.

Did you complete the repair?

--

System OK

--

5

  1. Disconnect the interior courtesy lamp/power sunroof control switch connector.
  2. Turn the ignition ON.
  3. Measure the voltage at terminal 5 of the interior courtesy lamp/power sunroof control switch connector.

Is the voltage within the specified range?

11-14 V

Go to Step 7

Go to Step 6

6

Repair the open circuit between fuse F8 and the interior courtesy lamp/power sunroof control switch connector.

Did you complete the repair?

--

System OK

--

7

  1. Reconnect the interior courtesy lamp/power sunroof control switch connector.
  2. With the sunroof switch in the OPEN position, measure the voltage at terminal 4 of the interior courtesy lamp/power sunroof control switch connector.
  3. With the sunroof switch in the CLOSE position, measure the voltage at terminal 6 of the interior courtesy lamp/power sunroof control switch connector.

Are both voltages within the specified range?

11-14 V

Go to Step 9

Go to Step 8

8

Replace the interior courtesy lamp/power sunroof control switch.

Did you complete the replacement?

--

System OK

--

9

  1. Disconnect the sunroof module connector.
  2. With the sunroof switch in the OPEN position, measure the voltage at terminal 1 of the sunroof module connector.
  3. With the sunroof switch in the CLOSE position, measure the voltage at terminal 6 of the sunroof module connector.

Are the voltages within the specified range?

11-14 V

Go to Step 11

Go to Step 10

10

Repair the open circuit between the interior courtesy lamp/power sunroof control switch and the sunroof module connector.

Did you complete the repair?

--

System OK

--

11

  1. Reconnect the sunroof module.
  2. Remove the sunroof motor, but leave the connectors attached.
  3. Turn the ignition ON.
  4. Use the sunroof switch to attempt to operate the motor in both directions.

Does the motor operate?

--

Go to Step 12

Go to Step 13

12

Repair the jammed sunroof mechanism.

Did you complete the repair?

--

System OK

--

13

  1. Disconnect both of the 1-wire connectors at the sunroof motor.
  2. Connect a voltmeter between the 1-wire connectors, on the module side of the connectors.
  3. Turn the ignition ON.
  4. Turn the sunroof switch to the OPEN position and observe the voltmeter reading.
  5. Turn the sunroof switch to the CLOSE position and observe the voltmeter reading, one of the switch positions should show reverse polarity

Does the voltmeter indicate within the specified voltage range when the switch is in either the OPEN or the CLOSE position?

11-14 V

Go to Step 15

Go to Step 14

14

Replace the sunroof module.

Did you complete the replacement?

--

System OK

--

15

Replace the sunroof motor.

Does the sunroof operate with the new motor?

--

System OK

Go to Step 14