GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

An intermittent or poor connection can cause the sunroof not to operate properly. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The steps below refer to the test steps in the diagnostic table.

  1. Testing the other sunroof switch input circuits for a reference voltage. If a reference voltage is not present, a short to ground in the input circuit will inhibit the system operation.

  2. Test for RAP relay switch supply voltage circuit of the sunroof module. If voltage is not present, go to the RAP Inoperative table.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

1

Did you perform the Power Sunroof Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Power Sunroof

2

Verify that the customer complaint is still present.

Does the sunroof operate OK?

--

Go to Diagnostic Aids

Go to Step 3

3

Inspect the RAP fuse for an open.

Is the fuse open?

--

Go to Step 16

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Open the driver door.
  3. Disconnect the sunroof switches harness connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage between the sunroof switch open signal circuit and the sunroof switch low reference circuit of the sunroof slide switch harness connector.

Is the voltage within the specified range?

10-15 V

Go to Step 6

Go to Step 5

5

Measure the voltage between the sunroof switch open signal circuit of the sunroof slide switch harness connector and a good ground.

Is the voltage within the specified range?

10-15 V

Go to Step 14

Go to Step 8

6

Measure the voltage between the other sunroof switch input circuits of the sunroof switches harness connector and a good ground.

Is the voltage within the specified range?

10-15 V

Go to Step 7

Go to Step 15

7

Connect a 3-amp fused jumper wire between the sunroof switch open signal circuit and the sunroof switch low reference circuit of the sunroof slide switch harness connector, for 3 seconds.

Does the sunroof open?

--

Go to Step 18

Go to Step 11

8

Measure the voltage between the other sunroof switch input circuits of the sunroof switches and a good ground.

Is the voltage within the specified range?

10-15 V

Go to Step 13

Go to Step 9

9

  1. Turn OFF the ignition.
  2. Open the driver door.
  3. Disconnect the sunroof module harness connector that contains the RAP relay switch supply voltage circuit.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the RAP relay switch supply voltage circuit and the ground circuit of the sunroof module harness connector.

Is the voltage within the specified range?

10-15 V

Go to Step 20

Go to Step 10

10

Measure the voltage between the RAP relay switch supply voltage circuit of the sunroof module harness connector and a good ground.

Is the voltage within the specified range?

10-15 V

Go to Step 22

Go to Retained Accessory Power (RAP) Inoperative in Retained Accessory Power

11

  1. Turn OFF the ignition.
  2. Open the driver door.
  3. Disconnect the sunroof motor harness connector.
  4. Measure the resistance of each sunroof motor control circuit from the sunroof motor harness connector to the sunroof module harness connector.

Is the resistance less than the specified value?

3 ohms

Go to Step 12

Go to Step 23

12

  1. Connect a 3-amp fused jumper wire between the sunroof switch open signal circuit and the sunroof switch low reference circuit of the sunroof slide switch harness connector, for 3 seconds.
  2. Measure the voltage between the sunroof motor control circuits of the sunroof module.

Ignoring polarity, is the voltage within the specified range?

10-15 V

Go to Step 21

Go to Step 19

13

Test the sunroof switch open signal circuit of the sunroof slide switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 20

14

Test the sunroof switch low reference circuit of the sunroof slide switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 20

15

Test the sunroof switch input circuit, that had no voltage for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 20

16

Test the RAP relay switch supply voltage circuit of the sunroof module for a short to ground. Refer to Circuit Testing and Wiring Repairs to in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 17

17

Test the sunroof motor control circuits of the sunroof module for short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 21

18

Inspect for a poor connection at the harness connector of the sunroof switches. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 24

19

Test the sunroof switch open signal circuit of the sunroof slide switch for a short to B+. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 20

20

Inspect for poor connection at the harness connector of the sunroof module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 25

21

Inspect for a poor connection at the harness connector of the sunroof motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

Go to Step 26

22

Repair an open or high resistance in the ground circuit of the sunroof module. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

--

23

Repair an open or high resistance in the sunroof motor control circuits of the sunroof module. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 27

--

24

Replace the sunroof slide switch. Refer to Sunroof Switch Replacement .

Did you complete the replacement?

--

Go to Step 27

--

25

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

Did you complete the replacement?

--

Go to Step 27

--

26

Important: Inspect the sunroof assembly for binding or mechanical failure.

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

Did you complete the replacement?

--

Go to Step 27

--

27

  1. Connect any disconnected connectors.
  2. Remove any jumper wires.
  3. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2