GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views , Computer/Integrating Systems Connector End Views , or Power Door Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Verify that the courtesy/dome lamps are always ON.

Do the courtesy/dome lamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Inspect the following modules for the proper applicable data parameters included in the list below:

    â€¢ Body Control Module (BCM)
    â€¢ Driver Door Module (DDM)
    â€¢ Passenger Door Module (PDM)
    â€¢ Liftgate Module (LGM)
    â€¢ Endgate Module (EGM)

Refer to Scan Tool Data List and Scan Tool Data Definitions for typical values and definitions:

    â€¢ The courtesy lamp switch
    â€¢ The interior lamp defeat switch
    â€¢ The door ajar switches
    â€¢ The liftglass ajar switch
    â€¢ The liftgate ajar switch
    â€¢ The upper left dome lamp switch

Was a problem found?

Go to Step 4

Go to Step 8

4

Disconnect and test the switch of the affected input circuit for proper continuity in the open and closed positions. Refer to Circuit Testing .

Is continuity present?

Go to Step 5

Go to Step 6

5

Test the signal and ground circuits of the affected input circuit for the following:

    â€¢ A short to ground
    â€¢ An open
    â€¢ A high resistance

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 7

6

Inspect for poor connections at the harness connector of the affected switch. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 9

7

Inspect for poor connections at the harness connector of the module in the affected circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 11

9

Replace the switch in the affected circuit. Refer to one of the following replacement procedures as applicable:

    â€¢  Headlamp Switch Replacement
    â€¢  Liftgate Latch Replacement

Did you complete the replacement?

Go to Step 12

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10

Replace the module in the affected circuit. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 12

--

11

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3