GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Roof 🢒 Sunroof 🢒 Power Sunroof Express Vent Open/Close Features Inoperative

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 is experiencing an intermittent inoperative condition, check the sunroof switch ground circuit for an open.

Test Description

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

  1. This step determines if the fault is the sunroof switch or the sunroof control module. It also tests the integrity of the express vent signal circuit. If the fuse in the jumper wire opens when you perform this test, a short to battery voltage may have occurred.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Sunroof Connector End Views

DEFINITION: The sunroof express vent open or close feature is inoperative. 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 roof vent through its full range of functions in order to verify that the vent express open/close features are inoperative.

Does the power sunroof vent express feature operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are both the vent express open and close functions inoperative?

--

Go to Step 4

Go to Step 6

4
  1. Disconnect the sunroof switch.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage from the vent express signal circuit of the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 7

5

  1. Connect the harness connector to the sunroof switch.
  2. Close the sunroof.
  3. Disconnect the sunroof switch.
  4. Connect a jumper wire between the vent express signal circuit of the switch connector and the vent open switch signal circuit of the switch connector.
  5. Connect one end of a 3-amp fused jumper wire to one end the previously connected jumper wire.
  6. Momentarily connect the other end of the 3-amp fused jumper wire to a good ground.

Did the roof express open to the vent position?

--

Go to Step 9

Go to Step 10

6
  1. Disconnect the sunroof switch.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage from the inoperative vent open or close switch signal circuit of the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 9

Go to Step 8

7

Test the vent express 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 13

Go to Step 10

8

Test the appropriate vent open or 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 13

Go to Step 10

9

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 13

Go to Step 11

10

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 13

Go to Step 12

11

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Have you finished the replacement?

--

Go to Step 13

--

12

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

Have you finished the replacement?

--

Go to Step 13

--

13

Operate the system to verify the repair.

Do you find and correct the condition?

--

System OK

Go to Step 2