B1348 – Heated Backlite Relay Circuit Open

The ODBII code B1348 indicates that there is an open circuit in the heated backlite relay, meaning the relay is not functioning properly or is not receiving power, preventing the heated backlite from operating.

The severity of ODBII code B1348 is moderate.

Common Causes For: B1347 Heated Backlite Relay Circuit Failure

• Faulty heated backlite relay
• Open or damaged wiring in the relay circuit
• Poor connections or corroded terminals
• Blown fuse related to the heated backlite system
• Faulty heated backlite switch
• Malfunctioning body control module (BCM)

Common misdiagnosis for B1348 Heated Backlite Relay Circuit Open

• Faulty heated backlite
• Bad relay
• Wiring issues
• Faulty body control module (BCM)
• Incorrectly diagnosed electrical short
• Malfunctioning switch
• Grounding issues

Common Troubleshooting Steps

The OBD-II code B1348 indicates a problem with the heated backlite relay circuit, specifically that the circuit is open. This can affect the operation of the rear defroster or heated back window. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information about the heated backlite relay circuit, including wiring diagrams and component locations.
• Visual Inspection:
• Inspect the wiring and connectors associated with the heated backlite relay for any signs of damage, corrosion, or loose connections.
• Check the relay itself for any physical damage.
• Test the Relay:
• Remove the heated backlite relay and test it using a multimeter. Check for continuity and ensure that it operates correctly when energized.
• If the relay is faulty, replace it with a new one.
• Check the Fuse:
• Locate the fuse associated with the heated backlite circuit and check if it is blown. If it is, replace it and see if the code returns.
• Inspect the Circuit:
• Use a multimeter to check for continuity in the wiring between the relay and the heated backlite. Look for any breaks or shorts in the wiring.
• Check for proper voltage at the relay connector when the circuit is activated.
• Check Ground Connections:
• Ensure that the ground connections for the heated backlite circuit are secure and free of corrosion. A poor ground can cause an open circuit.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue.
• Test the Heated Backlite:
• If all other components check out, test the heated backlite itself to ensure it is functioning properly. A malfunctioning backlite can sometimes cause the relay to fail.
• Clear the Code:
• After performing repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the B1348 code.