GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

If voltage is not measured on the sunroof switch open signal or sunroof switch close signal circuits, the fault could be in the retained accessory power (RAP) supply voltage circuit, battery positive voltage circuit, or sunroof motor ground circuit. If the sunroof motor is not being powered, neither will the sunroof switch signal circuits.

Test Description

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

  1. This step is used to determine the correct diagnostic path. The path depends on if the sunroof is inoperative and in the open position, or if the sunroof is inoperative and in the closed position.

  2. This step tests the sunroof switch open switch.

  3. This step tests the sunroof switch close switch.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Power Roof Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Attempt to operate the sunroof through its full range of functions in order to verify that the power sunroof inoperative fault is present.

Does the power sunroof system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Is the sunroof in the fully closed position?

--

Go to Step 4

Go to Step 7

4

  1. Disconnect the sunroof switch.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a 3-amp fused jumper wire to the low reference circuit of the sunroof switch harness connector.
  4. Connect the other end of the 3-amp fused jumper wire to the sunroof switch open signal circuit of the sunroof switch harness connector, for 3 seconds.

Did the sunroof open?

--

Go to Step 17

Go to Step 5

5

  1. Disconnect the 3-amp fused jumper wire.
  2. Measure the voltage from the sunroof switch open signal circuit of the sunroof switch harness connector to the low reference circuit of the sunroof switch harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 13

Go to Step 6

6

Measure the voltage from the sunroof switch open signal circuit of the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 14

Go to Step 10

7

  1. Disconnect the sunroof switch.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a 3-amp fused jumper wire to the low reference circuit of the sunroof switch harness connector.
  4. Connect the other end of the 3-amp fused jumper wire to the sunroof switch close signal circuit of the sunroof switch harness connector, for 3 seconds.

Did the sunroof close?

--

Go to Step 17

Go to Step 8

8

  1. Disconnect the 3-amp fused jumper wire.
  2. Measure the voltage from the sunroof switch close signal circuit of the sunroof switch harness connector to the low reference circuit of the sunroof switch harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 15

Go to Step 9

9

Measure the voltage from the sunroof switch close signal circuit of the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 14

Go to Step 10

10

  1. Disconnect the sunroof motor harness connector.
  2. Measure the voltage from the battery positive voltage circuit of the sunroof motor harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 11

Go to Step 19

11

Measure the voltage from the retained accessory power (RAP) supply voltage circuit of the sunroof motor harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 12

Go to Symptoms - Computer/Integrating Systems in Computer/Integrating Systems

12

  1. Turn OFF the ignition.
  2. Measure the resistance from the ground circuit of the sunroof motor harness connector to a good ground.

Does the resistance measure less than or equal to the specified value?

5 ohms

Go to Step 16

Go to Step 20

13

Test the sunroof switch close signal circuit 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 23

Go to Step 18

14

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

Did you find and correct the condition?

--

Go to Step 23

Go to Step 18

15

Test the sunroof switch open signal circuit 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 23

Go to Step 18

16

Test the appropriate sunroof switch signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 23

Go to Step 18

17

Inspect for poor connections at the harness connector of the sunroof switch. 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 23

Go to Step 21

18

Inspect for poor connections at the harness connectors 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 23

Go to Step 22

19

Repair the short to ground or open in the sunroof motor battery positive voltage circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

20

Repair the open in the sunroof motor ground circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

21

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Did you complete the replacement?

--

Go to Step 23

--

22

Replace the sunroof motor. Refer to Control Module References in Computer/Integrating Systems.

Did you complete the replacement?

--

Go to Step 23

--

23

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Step 2