WOMS
B code body Medium severity

B2586 Headlamp Mode Select Circuit Failure

The OBD2 code B2586 indicates a failure in the headlamp mode select circuit, which may affect the operation of the vehicle's headlight settings

Definition

The OBD2 code B2586 indicates a failure in the headlamp mode select circuit, which may affect the operation of the vehicle's headlight settings

Common causes

  • Faulty headlamp switch
  • Damaged wiring or connectors
  • Short circuit in the headlamp mode select circuit
  • Failed body control module (BCM)
  • Corroded terminals
  • Malfunctioning relay
  • Poor ground connection

Common misdiagnoses

  • Headlight bulb failure
  • Faulty headlight assembly
  • Wiring issues or shorts
  • Bad ground connection
  • Malfunctioning body control module (BCM)
  • Incorrectly installed or damaged connectors
  • Faulty switch or control stalk
  • Issues with the lighting control module

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues present

  2. 2. Inspect the Headlamp Switch

    Check the headlamp switch for proper operation. Ensure that it is not damaged or malfunctioning

  3. 3. Test the switch for continuity using a multimeter to ensure it is sending the correct signals

  4. 4. Examine Wiring and Connectors

    Inspect the wiring and connectors associated with the headlamp mode select circuit for any signs of damage, corrosion, or loose connections

  5. 5. Look for frayed wires, broken connectors, or any other physical damage

  6. 6. Test the Headlamp Relay

    If your vehicle uses a relay for the headlamp circuit, test the relay to ensure it is functioning properly. You can swap it with a similar relay in the fuse box to see if the problem persists

  7. 7. Check the Body Control Module (BCM)

    The BCM may control the headlamp mode select circuit. Check for any faults in the BCM and ensure it is receiving the correct inputs from the headlamp switch

  8. 8. If necessary, reprogram or replace the BCM

  9. 9. Inspect the Headlamps

    Ensure that the headlamps themselves are functioning correctly. Check for burnt-out bulbs or faulty connections at the headlamp assembly

  10. 10. Look for Ground Issues

    Check the ground connections related to the headlamp circuit. A poor ground can cause various electrical issues, including circuit failures

  11. 11. Perform a Visual Inspection

    Conduct a thorough visual inspection of the entire headlamp circuit, including fuses, wiring harnesses, and connectors, for any signs of wear or damage

  12. 12. Consult Wiring Diagrams

    Refer to the vehicle’s wiring diagrams to understand the headlamp circuit better and identify any potential points of failure

  13. 13. Clear Codes and Test Drive

    After performing repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.1

  14. 14. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B2586 code