GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The interior courtesy lights do not activate when the right front door or the rear liftgate door is open. The interior courtesy lights activate when the driver's door or a sliding door is open.

1

Did you perform the Body Control Module (BCM) Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

Perform the BCM Input/Output test:

  1. Turn off the IP dimmer switch.
  2. Turn the ignition switch to the LOCK position.
  3. Remove the BCM PRGRM fuse.
  4. Turn the ignition switch to the ACC position. The BCM sounds 4 chimes, indicating the BCM type installed on the vehicle.
  5. Within 1 second, turn the ignition switch from the ACC position to the LOCK position and back to the ACC position.
  6. The BCM sounds any stored DTCs.

  7. Turn the I/P dimmer switch to the DOME position.
  8. The BCM enters the Input/Output test.

  9. Cycle the IP dimmer switch from the DOME position to the OFF position and back to the DOME position in order to move to the next test.
  10. The BCM runs the Input/Output test in numerical order.

    The BCM flashes the fasten belts indicator and sounds the chime a number equivalent to the Input/Output test number:

    • Test 1 de-energizes CKT 1393 (protected courtesy light output).
    • Test 2 energizes CKT 1393.
    • Test 3 grounds CKT 690 (courtesy lights control).
    • Test 4 turns on the exterior lights.
    • Test 5 sounds the horn relay for 25 ms.
    • Test 6 turns on the security indicator lamp.
    • Test 7 turns off the theft security indicator lamp.
  11. Open and close the inoperative door.
  12. Listen to the chime.

Important: While the BCM is performing the Input/Output test, the chime sounds when any of the BCM inputs is activated. Example: The chime sounds when any Door is opened.

Does the chime sound when you open the inoperative door?

--

Go to Step 6

Go to Step 3

3

  1. Open the inoperative door.
  2. Use a test lamp in order to connect between B+ and the (BCM) connector C2 terminal C3 by backprobing.

Did the test lamp light?

--

Go to Step 6

Go to Step 4

4

  1. Disconnect the inoperative door lock switch electrical connector C1.
  2. For the right front door, use a test lamp in order to connect between B+ and the door lock switch harness connector C1 terminal  A.
  3. For the liftgate door, use a test lamp in order to connect between B+ and the door lock switch harness connector C1 terminal D.

Did the test lamp light?

--

Go to Step 5

Go to Step 7

5

  1. Disconnect the BCM connector C2.
  2. For the right front door, use a DMM in order to measure the resistance between the BCM harness connector C2 terminal C3 and the door lock switch harness connector  C1 terminal D.
  3. For the liftgate door, use a DMM in order to measure the resistance between the BCM harness connector C2  terminal  C3 and the door lock switch harness connector C1 terminal A.

Is the resistance within the specified range?

Less than 10 ohms

Go to Step 8

Go to Step 9

6

  1. Inspect the BCM connector C2 terminal C3 for poor terminal contact.
  2. Perform repairs as needed.

  3. If the BCM connector C2 terminal  C3 is OK, replace the BCM. Refer to Body Control Module Replacement

Did you complete the repair?

--

Go to Step 10

--

7

  1. For the right front door, repair the following conditions in CKT 750:
  2. • A poor connection
    • An open
  3. For the liftgate door, repair the following conditions in CKT 450:
  4. • A poor connection
    • An open

Did you complete the repair?

--

Go to Step 10

--

8

Replace the inoperative door lock switch assembly.

Did you complete the repair?

--

Go to Step 10

--

9

Repair the following conditions in CKT 49:

    • A poor connection
    • An open

Did you complete the repair?

--

Go to Step 10

--

10

  1. Turn the ignition switch to the LOCK position.
  2. Reinstall any connectors or components that you removed.
  3. Turn the ignition switch to the RUN position for 6 seconds.
  4. Turn the ignition switch to the LOCK position.
  5. Remove the BCM PRGRM fuse.
  6. Turn the ignition switch to the ACC position.
  7. The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle.

  8. Within 1 second, turn the ignition switch from the ACC position to the LOCK position, then back to the ACC position.
  9. The BCM sounds any DTCs stored.

Are there any BCM DTCs present?

--

Go to Diagnostic System Check - Body Control System

Go to Interior Lamps System Check