GM Service Manual Online
For 1990-2009 cars only

Test Description

The number below refers to the step number on the diagnostic table.

  1. If the system does close properly, then suspect either the sunroof limit switch soft stop signal circuit or the sunroof limit switch low reference circuit for a poor connection or intermittent.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Power Roof Systems Connector End Views

DEFINITION: Sunroof does not automatically stop in the flush closed position.

1

Did you perform the Power Sunroof Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Power Sunroof

2

Operate the power sunroof to the close position.

Does the system close properly?

--

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

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Operate the sunroof switch to raise the sunroof glass to the vent position.
  3. Using a DVM, measure between the reference voltage of the sunroof limit switch soft stop signal circuit of the limit switch harness connector and ground.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 4

4

  1. Disconnect the connector to the limit switch.
  2. Using a DVM, measure between the reference voltage of the sunroof limit switch soft stop signal circuit of the limit switch harness connector and ground.

Does the voltage measure near the specified value?

B+

Go to Step 12

Go to Step 9

5

Using a DVM, measure between the reference voltage between the sunroof limit switch soft stop signal circuit and the sunroof limit switch low reference circuit of the limit switch harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 6

Go to Step 7

6

While measuring the reference voltage between the sunroof limit switch soft stop signal circuit and the sunroof limit switch low reference circuit, toggle the sunroof switch to slide the sunroof glass in small increments, back and forth through the flush closed position.

Did the voltage measure near the specified value as the sunroof past through the flush closed position?

0 V

Go to Step 13

Go to Step 10

7

Test the sunroof limit switch low reference 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 14

Go to Step 8

8

Inspect the sunroof limit switch low reference circuit for a poor connection. 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 14

Go to Step 13

9

Test the sunroof limit switch soft stop signal circuit for the following:

    • An open
    • A short to ground
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

10

Inspect the limit switch connector for a poor connection. 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 14

Go to Step 12

11

Inspect the limit switch soft stop signal circuit for a poor connection. 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 14

Go to Step 13

12

Replace the sunroof motor. Refer Sunroof Motor/Actuator Replacement .

Did you complete the replacement?

--

Go to Step 14

--

13

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

Did you complete the replacement?

--

Go to Step 14

--

14

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

Did you correct the condition?

--

System OK

Go to Step 3