GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics Body Control System Schematics in Computer/Integrating Systems

Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the interior backlighting is inoperative.

Does the interior backlighting operate normally?

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

Go to Step 3

3

Are all of the interior backlighting lamps inoperative?

Go to Step 5

Go to Step 4

4

Test for an open or high resistance in the following circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • The backlight lamps control
    • The instrument panel lamps dimming control
    • The ground

Did you find and correct a condition?

Go to Step 10

Go to Step 6

5

Test for a high resistance, an open, a short to ground, or a short to voltage in the following circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • 5-volt reference
    • The dimming input
    • The dimming return

Did you find and correct a condition?

Go to Step 10

Go to Step 7

6

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

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Replace the affected lamp or internal lamp component.

Did you complete the replacement?

Go to Step 10

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9

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

Did you complete the replacement?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3