GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

The BCM does not sound the headlamps on reminder during the following instances:

    • The driver's door is open.
    • The headlamp switch is in either the PARK or the HEAD position.
    • The ignition switch is in the LOCK, OFF, or ACC position.

1

Was the BCM Diagnostic System Check performed?

--

Go to Step 2

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

2

  1. Ensure that the IP dimmer switch is OFF.
  2. Turn the ignition switch to RUN.
  3. Lower the driver's window in order to prevent lockout.
  4. Close all of the vehicle doors.
  5. While observing the courtesy lights, open and then close the driver's door.

Did the courtesy lights turn on with the driver's door open?

--

Go to Step 3

Go to Step 7

3

  1. Ensure that the IP dimmer switch is off.
  2. Close all of the vehicle doors.
  3. Turn the ignition switch from RUN to LOCK.
  4. While observing the courtesy lights, remove the key from the ignition key cylinder.

Did the courtesy lights turn on when the key was removed from the ignition key cylinder?

Go to Step 4

Go to Step 8

4

  1. Connect a scan tool to the data link connector (DLC).
  2. Use the scan tool in order to monitor the park lamp off input.
  3. While observing the scan tool, turn the headlamp switch from OFF to HEAD and back to OFF.

Does the scan tool indicate park lamp off input active with the headlamp switch off?

--

Go to Step 9

Go to Step 5

5

  1. Turn the ignition switch to LOCK.
  2. Disconnect the BCM connector C1.
  3. Turn the headlamp switch to HEAD.
  4. Use a DMM in order to measure the voltage between the BCM connector C1 terminal C2 and ground.

Is the voltage less than the specified value?

2V

Go to Step 9

Go to Step 6

6

  1. Leave the DMM connected from the previous step.
  2. Disconnect the headlamp switch electrical connector.
  3. Measure the voltage again.

Is the voltage less than the specified value?

2V

Go to Step 10

Go to Step 11

7

The headlamp on reminder is inoperative due to a malfunction between the BCM and the driver's door lock ajar switch. Refer to Diagnostic System Check - Lighting Systems in Lighting Systems for further diagnosis.

Is the action complete?

--

Go to Step 12

--

8

The headlamp on reminder is inoperative due to a malfunction between the BCM and the ignition key alarm switch. Refer to Key-in-Ignition Chime Always On for further diagnosis.

Is the action complete?

--

Go to Step 12

--

9

  1. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.
  2. Perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Is the repair complete?

--

Go to Step 12

--

10

Replace the headlamp switch assembly. Refer to Headlamp Switch Replacement in Lighting Systems.

Is the repair complete?

--

Go to Step 12

--

11

Repair the short to B+ in circuit 1872.

Is the repair complete?

--

Go to Step 12

--

12

  1. Turn the ignition switch to LOCK.
  2. Reconnect the connectors and reinstall the components that were removed.
  3. Inspect for BCM current DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying in Body Control System.

Are there any BCM current DTCs present?

--

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

Go to Audible Warnings System Check