GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

The sunroof limit switch soft stop signal circuit can cause the sunroof not to respond correctly, if it were an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If the circuits test OK, an intermittent or poor connection can also cause the sunroof not to operate normally. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End Views Reference: Power Roof Systems Connector End Views

DEFINITION: The sunroof glass will only move slightly in between the vent and closed position.

1

Did you review the Power Sunroof Description and Operation?

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Go to Step 2

Go to Symptoms - Roof

2

Operate the power sunroof system.

Does the system operate normally?

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Go to Diagnostic Aids

Go to Step 3

3

Measure the reference voltage of the sunroof limit switch soft stop signal circuit at the sunroof control harness connector to a good ground.

Does the reference voltage measure near the specified value?

4.5-5.5 V

Go to Step 4

Go to Step 8

4

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. Connect a jumper wire to the sunroof limit switch soft stop signal circuit at the sunroof control module harness to a good ground.
  2. Turn ON the ignition, with the engine OFF.
  3. Using the sunroof switch, operate the sunroof system, not to exceed the full open soft stop position.

Does the system operate as requested?

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Go to Step 5

Go to Step 10

5

Test the sunroof limit switch soft stop signal 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 11

Go to Step 7

6

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

Did you find and correct the condition?

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Go to Step 11

Go to Step 7

7

Inspect for a poor connection at the harness connection of the soft stop limit switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 11

Go to Step 9

8

Inspect for poor connection at the harness connector of 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 11

Go to Step 10

9

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

Did you complete the replacement?

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Go to Step 11

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10

Replace the sunroof control module. Refer to Sunroof Control Module Replacement .

Did you complete the replacement?

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Go to Step 11

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11

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

Did you correct the condition?

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System OK

Go to Step 2