GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Monte Carlo 🢒 DTC 🢒 DTC B2665

Circuit Description

The headlamp switch provides a ground input into the body control module (BCM) for the park lamp switch input when the switch is activated. This input is used by the BCM to control the park lamps.

Conditions for Running the DTC

The headlamp switch must be in the PARK position.

Conditions for Setting the DTC

The BCM detects a short to battery or open in the park lamp circuit when the headlamp switch is in the PARK position.

Action Taken When the DTC Sets

The BCM stores DTC B2665 in memory.

Conditions for Clearing the DTC
    • A current DTC B2665 will clear if the BCM no longer detects a short to battery or open in the park lamp switch signal circuit.
    • A history DTC B2665 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • A scan tool may be used to clear the DTC.

Diagnostic Aids
    • If the DTC B2665 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to battery or open in the park lamp switch input circuit.
       - The headlamp switch is intermittently open internally.
       - The BCM is intermittently shorted to battery or open internally.

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check ?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2
  1. Install a scan tool.
  2. Make sure the headlamp switch is in the off position.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Park Lamp input parameter in the body control module (BCM) input data list.

Does the scan tool display Inactive?

Go to Step 3

Go to Step 4

3
  1. Turn the headlamp switch to the park lamp position.
  2. With the scan tool, observe the park lamp input parameter.

Does the park lamp input parameter change state?

Go to Diagnostic Aids

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the headlamp switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the park lamp switch input parameter.

Does the scan tool display Inactive?

Go to Step 7

Go to Step 5

5

Test the park lamp switch signal circuit for a short to battery positive voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

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

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

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

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Important: Perform the set up procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 10

--

9

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK