GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The courtesy lamps do not turn on when the I/P lamp dimmer switch is in the DOME position. The courtesy lights turn on when any door is open.

1

  1. Turn the ignition switch off.
  2. Connect scan tool to Data Link Connector (DLC).
  3. Turn the ignition switch on.
  4. Using scan tool, monitor the status of the COURTESY LAMP SWITCH.
  5. While observing the scan tool, turn the I/P lamp dimmer switch from off to DOME, back to off.

Does the scan tool display that the status of the COURTESY LAMP SWITCH is ON when the I/P lamp dimmer switch is in the DOME position?

--

Go to Step 5

Go to Step 2

2

  1. Turn the I/P dimmer switch to the DOME position.
  2. Using a test light, connect by backprobing between the Body Control Module (BCM) connector C1 terminal D15 and B+

Is the test light on?

--

Go to Step 5

Go to Step 3

3

  1. Disconnect the I/P lamp dimmer switch electrical connector.
  2. Using a test light, connect between the I/P lamp dimmer switch harness connector terminal A and B+.

Is the test lamp on?

--

Go to Step 4

Go to Step 6

4

  1. Turn the ignition switch off.
  2. Disconnect the BCM connector C1.
  3. Using a DMM, measure the resistance between the BCM harness connector C1 terminal D15 and the I/P lamp dimmer switch harness connector terminal E.

Is the resistance within the specified range?

Less than 2ohms

Go to Step 7

Go to Step 8

5

  1. Turn the ignition switch off.
  2. Disconnect the scan tool from the DLC.
  3. Turn the ignition switch on.
  4. Close all the vehicle doors.
  5. While observing the courtesy lamps, turn the I/P lamp dimmer switch to the DOME position.

Do the courtesy lamps turn on when the I/P lamp dimmer switch is in the DOME position?

--

Go to Step 9

Go to Step 10

6

Repair poor connection or open in circuit 1750.

Is the repair complete?

--

Go to Step 11

--

7

Replace the I/P lamp dimmer switch assembly. Refer to Instrument Panel Multifunction Switch Assembly Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Step 11

--

8

Repair poor connection or open in circuit 1495.

Is the repair complete?

--

Go to Step 11

 

9

The malfunction is not present at this time. Refer to Interior Lights Circuit Description for more information regarding the operation of the courtesy lamps.

Is the action complete?

--

Go to Step 11

--

10

  1. Inspect the BCM connector C1 terminal D15 for a poor terminal contact. Perform the repairs as necessary.
  2. If the BCM connector C1 terminal D15 is OK, then replace the BCM. Refer to Body Control Module Replacement in Body Control System.
  3. After BCM replacement, perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Is the action complete?

--

Go to Step 11

--

11

  1. Turn the ignition switch off.
  2. Reinstall the connectors/components removed.
  3. Check for the BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying in Body Control System.

Are there any DTCs stored in the BCM?

--

Go to Diagnostic System Check - Body Control System in Body Control System

System OK