GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Power and Grounding Connector End Views in Wiring Systems

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the headlamp switch to the OFF position.
  2. Close all doors.

Are all of the courtesy lamps OFF?

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

Go to Step 3

3

Disconnect the headlamp switch.

Are the courtesy lamps on?

Go to Step 4

Go to Step 11

4

Test the courtesy lamp switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 5

5

Disconnect the BCM connector C1.

Using a test lamp connected to battery positive voltage, probe the courtesy lamp low control circuit at the BCM harness connector.

Does the test lamp illuminate?

Go to Step 8

Go to Step 6

6

  1. Reconnect the BCM connector C1.
  2. Disconnect each door lock ajar switch one at a time.

Do the courtesy lamps turn off when you disconnect any of the door lock ajar switches?

Go to Step 9

Go to Step 7

7

Test each door switch courtesy open circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Repair a short to ground in the courtesy lamps low control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

--

9

Replace the door lock ajar switch. Refer to Front Side Door Lock Replacement or Rear Door Lock Replacement in Doors.

Did you complete the replacement?

Go to Step 12

--

10

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Step 12

--

11

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

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