WOMS
B code body Medium severity

B1347 Heated Backlite Relay Circuit Failure

The OBD2 code B1347 indicates a failure in the heated backlite relay circuit, which is responsible for controlling the rear window defroster

Definition

The OBD2 code B1347 indicates a failure in the heated backlite relay circuit, which is responsible for controlling the rear window defroster

Common causes

  • Faulty heated backlite relay
  • Damaged wiring or connectors in the relay circuit
  • Short circuit in the heated backlite circuit
  • Open circuit in the heated backlite circuit
  • Faulty heated backlite switch
  • Malfunctioning body control module (BCM)
  • Corrosion or poor connections in the relay or circuit components

Common misdiagnoses

  • Faulty heated backlite switch
  • Defective body control module (BCM)
  • Wiring issues or shorts in the circuit
  • Malfunctioning relay
  • Faulty heated backlite element
  • Incorrectly diagnosed as a general electrical issue
  • Misinterpretation of other related codes
  • Battery or charging system problems

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the heated backlite system and the relay circuit

  2. 2. Visual Inspection

    Inspect the wiring and connectors associated with the heated backlite relay for any signs of damage, corrosion, or loose connections

  3. 3. Check the heated backlite itself for any cracks or damage

  4. 4. Test the Relay

    Locate the heated backlite relay in the fuse box or relay panel

  5. 5. Remove the relay and test it using a multimeter to ensure it is functioning properly. You can also swap it with a similar relay (if available) to see if the issue persists

  6. 6. Check Fuses

    Inspect the fuses related to the heated backlite circuit. Replace any blown fuses and check if the problem is resolved

  7. 7. Test the Heated Backlite

    Use a multimeter to check for continuity in the heated backlite element. If there is no continuity, the element may be faulty and needs replacement

  8. 8. Check for Power and Ground

    Use a multimeter to check for power at the relay and the heated backlite circuit when the system is activated. Ensure that the relay is receiving power and that the ground connection is solid

  9. 9. Scan for Additional Codes

    Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  10. 10. Inspect the Control Module

    If all other components check out, the issue may lie within the control module that manages the heated backlite system. Inspect for any faults or failures in the module

  11. 11. Consult a Professional

    If you are unable to diagnose or resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle model

  12. 12. Clear Codes and Test Drive

    After performing repairs, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns. By following these steps, you should be able to identify and resolve the issue related to the B1347 code. Always ensure safety precautions are taken when working on electrical systems in vehicles