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 , Data Communication Connector End Views, or Master Electrical Component List

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

Test for a ground signal on the liftgate ajar signal circuit of the liftgate ajar switch.

Was a ground signal present?

Go to Step 5

Go to Step 4

4

  1. Ensure that the instrument panel lamp dimmer switch is in the minimum brightness position.
  2. Inspect for the following related body control module (BCM), driver door module (DDM), and passenger door module (PDM) data parameters. Refer to Scan Tool Data List and Scan Tool Data Definitions for typical values and definitions:
  3. • The courtesy lamp switch
    • The interior lamp defeat switch
    • The door ajar switches

Was a problem found?

Go to Step 5

Go to Step 9

5

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

Is continuity correct in both positions?

Go to Step 6

Go to Step 7

6

Test the signal circuits of the affected input switch for a short to ground or the courtesy lamp defeat switch signal circuit for an open. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 13

Go to Step 8

7

Inspect for poor connections at the harness connector of the affected switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

8

Inspect for poor connections at the harness connector of the module in the affected circuit. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Replace the switch in the affected circuit.

Did you complete the replacement?

Go to Step 13

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11

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 13

--

12

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

Did you complete the replacement?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3