GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

DEFINITION: The courtesy lamps do not turn off with the switch in the DOOR position and all doors closed, or the courtesy lamp defeat feature of the switch is inoperative.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. With a door open, place the instrument panel (I/P) dimmer switch in the defeat position.
  3. Place the I/P dimmer switch in the DOOR position.
  4. Close all of the vehicle doors.
  5. Wait 20 seconds.

Do the lamps illuminate as expected?

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

Go to Step 3

3

Is the complaint that the courtesy lamps operate with the switch in the defeat position?

Go to Step 4

Go to Step 5

4

Test the courtesy lamps switch off signal circuit of the interior lamps switch an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 14

5

Use the scan tool in order to command the courtesy lamps OFF.

Do the courtesy lamps turn OFF?

Go to Step 6

Go to Step 9

6

  1. Close all of the vehicle doors.
  2. With a scan tool, observe the Door Open Switch and Liftgate Open Switch parameters in the data list.

Does the scan tool indicate that all parameters are Closed?

Go to Step 7

Go to Step 10

7

Disconnect the I/P dimmer switch.

Are the courtesy lamps illuminated?

Go to Step 8

Go to Step 12

8

Test for a short to ground in the courtesy lamp switch ON signal circuit 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 17

Go to Step 13

9

Test the courtesy lamp high control circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 13

10

  1. Disconnect the door jamb, lock, or liftgate switches that indicate an open door while the door is closed.
  2. Observe the appropriate switch parameter.

Does the scan tool indicate that the parameters are Closed when the switches are disconnected?

Go to Step 15

Go to Step 11

11

Test the open 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 17

Go to Step 13

12

Inspect for poor connections at the harness connector of the I/P dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 14

13

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

Did you find and correct the condition?

Go to Step 17

Go to Step 16

14

Replace the I/P dimmer switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 17

--

15

Replace the inoperative switch. Refer to the following:

    •  Front Side Door Lock Replacement in Doors
    •  Liftgate Latch Replacement in Body Rear End

Did you complete the replacement?

Go to Step 17

--

16

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 17

--

17

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2