GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

DEFINITION: The dome lamp, roof rail courtesy lamps, and the front side door courtesy lamps are on all the time with the ignition in RUN and all the doors closed, or remain on for 10 minutes after closing the doors with the ignition in LOCK.

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 ignition switch to the RUN position.
  2. Close all the doors.
  3. Verify that all the courtesy lamps illuminate and then go off after 20 seconds.

Do the courtesy lamps turn off after 20 seconds?

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

Go to Step 3

3

  1. Turn ignition switch to the RUN position, with the engine OFF.
  2. With a scan tool, observe the courtesy switch input data.
  3. Pull the interior lamps switch in order to turn on and off the interior lamps.

Does the scan tool indicate that the courtesy switch input parameter changes when the interior lamp switch is pulled?

Go to Step 5

Go to Step 4

4

Test for a short to ground in the Interior lamp switch signal circuit (XY112). Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 7

5

Test for a short to ground in the courtesy lamps ground circuit (XP803) of the interior lamps relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

6

Replace the multifunction relay K134.

Is the repair complete?

Go to Step 8

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7

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Is the repair complete?

Go to Step 8

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8

  1. Connect all the connectors and components that were disconnected.
  2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2