GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The BCM sounds the headlamps on reminder when one or more of the following conditions are present:

    • The driver's door is closed.
    • The headlamp switch is in the OFF 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 the on position.
  3. Lower the driver's window in order to prevent lockout.
  4. Close all of the vehicle doors.

Are the courtesy lamps off?

--

Go to Step 3

Go to Step 7

3

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

Does the scan tool indicate that the park lamp off input is on while the headlamp switch was in the OFF position?

--

Go to Step 8

Go to Step 4

4

  1. Turn the headlamp switch to the OFF position.
  2. Using a test light, connect between the BCM connector C2 terminal A2 and ground.

Is the test light on?

--

Go to Step 8

Go to Step 5

5

  1. Disconnect C201.
  2. Using a test light, connect between C201 terminal Z (male side of the connector) and ground.

Is the test light on?

--

Go to Step 6

Go to Step 9

6

  1. Disconnect the BCM connector C1.
  2. Using a DMM, measure the resistance between the BCM harness connector C2 terminal A2 and C201 terminal T (male side of the connector) and ground.

Is the resistance less than the specified value?

2 ohms

Go to Step 10

Go to Step 11

7

The headlamps on reminder is on with the driver's door closed due to a malfunction between the BCM and the driver's door lock ajar switch. Refer to Diagnostic System Check - Lighting Systems for diagnosis and repair of the interior lights door lock ajar input.

Is the action complete?

--

Go to Step 12

 

8

  1. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.
  2. After the BCM replacement, 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

--

9

Repair poor connection or open in circuit 1340.

Is the repair complete?

--

Go to Step 12

--

10

  1. Inspect C201 terminals T and Z for a poor connection.
  2. If the connection is OK, replace the headlamp switch. Refer to Turn Signal and Multifunction Switch Assembly - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt .

Is the repair complete?

--

Go to Step 12

--

11

Repair poor connection or open in circuit 1872.

Is the repair complete?

--

Go to Step 12

--

12

  1. Turn the ignition switch off.
  2. Reconnect the connectors and reinstall the components that you removed.
  3. Inspect for BCM current DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying .

Are there any BCM current DTCs present?

--

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

System OK