WOMS
B code body Medium severity

B1349 Heated Backlite Relay Short To Battery

The OBD2 code B1349 indicates a malfunction related to the heated backlite relay, specifically a short circuit to the battery, which means the relay is receiving power continuously instead of being controlled properly

Definition

The OBD2 code B1349 indicates a malfunction related to the heated backlite relay, specifically a short circuit to the battery, which means the relay is receiving power continuously instead of being controlled properly

Common causes

  • Shorted wiring or connectors
  • Faulty heated backlite relay
  • Malfunctioning body control module (BCM)
  • Corroded or damaged electrical connections
  • Faulty heated backlite element
  • Incorrectly installed or damaged fuses

Common misdiagnoses

  • Faulty heated backlite relay
  • Shorted wiring or connectors
  • Malfunctioning body control module (BCM)
  • Defective heated backlite element
  • Issues with the power supply circuit
  • Incorrectly installed or damaged fuses
  • Faulty ground connections

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the heated backlite relay and its circuit. This can provide valuable insights into the wiring diagrams and component locations

  2. 2. Visual Inspection

    Inspect Wiring and Connectors: Look for any damaged, frayed, or corroded wires and connectors related to the heated backlite relay. Pay special attention to areas where wires may rub against metal or other components

  3. 3. Check the Relay

    Locate the heated backlite relay and inspect it for any signs of damage or corrosion

  4. 4. Test the Relay

    Swap the Relay: If the relay is removable, consider swapping it with a similar relay in the fuse box to see if the problem persists

  5. 5. Bench Test the Relay

    If you have the means, test the relay outside of the vehicle to ensure it operates correctly

  6. 6. Check for Short Circuits

    Use a Multimeter: Set a multimeter to the continuity setting and check for shorts in the wiring harness leading to the relay. Look for continuity where there shouldn’t be any (e.g., between the relay terminals and ground)

  7. 7. Inspect Ground Connections

    Ensure that all ground connections related to the heated backlite system are secure and free of corrosion

  8. 8. Inspect the Heated Backlite Circuit

    Check for Shorts to Battery: Trace the wiring from the relay to the heated backlite and check for any shorts to battery voltage. This may involve checking the circuit for continuity to ground and ensuring that the circuit is not inadvertently connected to battery voltage

  9. 9. Check the Heated Backlite Element

    Inspect the Backlite: If accessible, check the heated backlite element for any signs of damage or failure. A short in the element itself could cause the relay to trigger a fault code

  10. 10. 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

  11. 11. Clear the Code and Test Drive

    After performing the above checks and repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  12. 12. Consult a Professional

    If the issue persists after performing these steps, it may be best to consult a professional mechanic or an automotive electrician for further diagnosis.Safety Precautions - Always disconnect the battery before working on electrical components to prevent shocks or shorts. - Ensure that you are working in a safe environment, especially when dealing with electrical systems. By following these steps, you should be able to identify and resolve the issue related to the B1349 code