GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics or Body Control System Schematics

Connector End View Reference: Lighting Systems Connector End Views or Data Communication 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 inoperative.

Do the courtesy/dome lamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are all courtesy lamps inoperative?

Go to Step 5

Go to Step 4

4

Test the voltage supply and ground circuits of the inoperative lamp for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 16

Go to Step 14

5

Are the courtesy lamps inoperative from a specific switch only?

Go to Step 6

Go to Step 11

6

Inspect the following related body control module (BCM), driver door switch, passenger door switch data parameters. Refer to Scan Tool Data List and Scan Tool Data Definitions for typical values and definitions:

    • Ctsy. Lamp Actv. Reason
    • Driver Door Open Sw.
    • Passenger Door Open Sw.

Was a problem found?

Go to Step 7

Go to Step 10

7

Disconnect and test the switches 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 8

Go to Step 9

8

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

    • An open
    • A short to ground
    • High resistance
        Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 16

Go to Step 10

9

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 16

Go to Step 12

10

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 16

Go to Step 13

11

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 16

Go to Step 15

12

Replace the switch in the affected circuit.

Did you complete the replacement?

Go to Step 16

--

13

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 16

--

14

Replace the inoperative bulb.

Did you complete the repair?

Go to Step 16

--

15

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

Did you complete the replacement?

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3