GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

If the sunroof is experiencing an intermittent inoperative condition, check the sunroof switch ground circuit for an open. If the sunroof switch ground circuit is open, the switch may take a redundant path to ground through the switch illumination circuit. When the lights are turned On, the redundant path to ground is removed and the sunroof will become inoperative.

If the sunroof close signal circuit is found to be short to voltage, the sunroof switch will most likely be open.

Test Description

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

  1. This step tests the integrity sunroof close switch. If the sunroof closes from the open position when performing this test, the switch is at fault. If the fuse in the jumper wire opens when you perform this test, a short to battery voltage may have occurred.

Step

Action

Value

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View: Sunroof Connector End Views

DEFINITION: The sunroof will not close from the open position using the roof close switch. However, the roof will close from the open position by using the vent close switch or vent express close switch. All other sunroof functions operate OK.

1

Have you conducted Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Attempt to operate the power sunroof through its full range of functions in order to verify that the power sunroof does not close from the open position.

Does the Power Sunroof System operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the sunroof switch.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a 3-amp fused jumper wire between the roof close switch signal circuit of the switch connector and the ground circuit of the switch connector.

Did the power sunroof move to the closed position?

--

Go to Step 6

Go to Step 4

4

  1. Disconnect the 3-amp fused jumper wire.
  2. Measure the voltage from the sunroof close switch signal circuit of the sunroof switch connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 7

Go to Step 5

5

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

Do you find and correct the condition?

--

Go to Step 10

Go to Step 7

6

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

Do you find and correct the condition?

--

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connectors of the sunroof control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Do you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Have you finished the replacement?

--

Go to Step 10

--

9

Replace the sunroof control module. Refer to Control Module References .

Have you finished the replacement?

--

Go to Step 10

--

10

Operate the system to verify the repair.

Do you find and correct the condition?

--

System OK

Go to Step 2