GM Service Manual Online
For 1990-2009 cars only

Test Description

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

  1. Using a jumper wire to jump between the sunroof limit switch soft stop signal circuit and the sunroof limit switch low reference circuit, will simulate that the sunroof glass is in a position other than close or full open position. This will allow any request from the sunroof switch to supply an output to drive the sunroof motor for testing the status of the limit switches.

  2. Checking the sunroof motor open and close output circuits, both should be at ground potential when idle.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End Views Reference: Power Roof Systems Connector End Views

1

Did you review the Power Sunroof Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Roof

2

Operate the power sunroof.

Does the system operate normally?

--

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

Go to Step 3

3

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

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 4

Go to Step 13

4

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

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 5

Go to Step 18

5

Measure the reference voltage between the sunroof switch close signal circuit and the sunroof switch low reference circuit at the sunroof switch harness connector.

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 6

Go to Step 22

6

  1. Connect one end of a jumper wire to the sunroof switch low reference circuit of the sunroof switch harness connector.
  2. Depending on the position of the sunroof, try to operate the sunroof by connecting the other end of the jumper wire to each of the:
  3. • Sunroof switch open signal circuit
    • Sunroof switch close signal circuit

Does the system operate normally?

--

Go to Step 28

Go to Step 7

7

Notice: Do not open the sunroof glass past the full open soft stop position. Doing so may damage the sunroof assembly and or the roof top.

  1. Reconnect the sunroof switch to the harness connector.
  2. Connect a jumper wire between the sunroof limit switch soft stop signal circuit and the sunroof limit switch low reference circuit at the sunroof control module harness connector.
  3. Observing the position of the sunroof glass, operate the system by pressing the sunroof switch to slide the glass to the available positions, open then closed or closed then open, not exceeding the full open soft stop position.

Did the sunroof glass slide as requested?

--

Go to Step 8

Go to Step 11

8

Test the sunroof limit switch range signal circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 9

9

Test the sunroof limit switch low reference circuit 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 39

Go to Step 32

10

Test the sunroof limit switch low reference 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 39

Go to Step 11

11

  1. Disconnect the sunroof motor connector.
  2. Connect a test lamp between the sunroof motor open and motor close circuits at the sunroof motor harness connector module side.

Does the test lamp illuminate?

--

Go to Step 37

Go to Step 12

12

  1. Leave the test lamp between the sunroof motor open and motor close circuits at the sunroof motor harness connector module side.
  2. While observing the test lamp, press the sunroof switch for three seconds to the close position then for three seconds to the open position.

Does test lamp illuminate with each command?

--

Go to Step 30

Go to Step 23

13

Did the reference voltage of the sunroof switch open signal circuit measure near the specified value?

B+

Go to Step 14

Go to Step 15

14

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

Does the voltage measure near the specified value?

B+

Go to Step 17

Go to Step 26

15

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

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 19

Go to Step 16

16

  1. Disconnect the sunroof control module harness connector that contains the sunroof ignition 3 voltage circuit.
  2. Turn the ignition ON, with the engine OFF.
  3. Measure the sunroof ignition 3 voltage circuit at the sunroof control module harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 29

Go to Step 27

17

Measure between the sunroof ignition 3 voltage circuit and the ground circuit at the sunroof control module harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 29

Go to Step 33

18

Did the reference voltage of the sunroof switch close signal circuit measure near the specified value?

B+

Go to Step 21

Go to Step 20

19

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

Did you find and correct the condition?

--

Go to Step 39

Go to Step 29

20

Test for an open, high resistance or short to ground in the sunroof switch close signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 29

21

Test the sunroof switch close signal circuit 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 39

Go to Step 37

22

Test the sunroof switch low reference circuit for an open, high resistance or a short to B+. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 29

23

Did the test lamp illuminate with either command?

--

Go to Step 23

Go to Step 25

24

Test both sunroof motor control circuits 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 39

Go to Step 29

25

Test both sunroof motor control circuits 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 39

Go to Step 29

26

Test the sunroof switch open signal circuit 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 39

Go to Step 37

27

Test the ignition 3 voltage circuit for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 31

28

Inspect for a poor connection at the sunroof switch harness connector. 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 39

Go to Step 36

29

Inspect for a poor connection at the sunroof control 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 39

Go to Step 37

30

Inspect for poor connections at 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 39

Go to Step 38

31

Inspect for poor connections at the PWR WDO CB circuit breaker. 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 39

Go to Step 34

32

Inspect for poor connections at the limit 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 39

Go to Step 35

33

Repair the ground circuit of the sunroof control module for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 39

--

34

Replace the circuit breaker.

Did you complete the repair?

--

Go to Step 39

--

35

Replace the sunroof limit switch. Refer to Sunroof Motor/Actuator Replacement .

Did you complete the repair?

--

Go to Step 39

--

36

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Did you complete the replacement?

--

Go to Step 39

--

37

Replace the sunroof control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 39

--

38

Replace the sunroof actuator. Refer to Sunroof Motor/Actuator Replacement .

Did you complete the replacement?

--

Go to Step 39

--

39

  1. Turn OFF the ignition.
  2. Disconnect any jumper wires.
  3. Reconnect all previously disconnected components.
  4. Turn the ignition ON, with the engine OFF.
  5. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3