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B1245 Wiper Rear Motor Run Relay Circuit Short to Battery

The OBD2 code B1245 indicates a short circuit in the rear wiper motor run relay circuit, meaning the circuit is receiving power continuously as if it is connected directly to the battery, which can cause the rear wiper...

Definition

The OBD2 code B1245 indicates a short circuit in the rear wiper motor run relay circuit, meaning the circuit is receiving power continuously as if it is connected directly to the battery, which can cause the rear wiper to malfunction

Common causes

  • Shorted wiring or connectors in the rear wiper motor circuit
  • Faulty rear wiper motor
  • Defective wiper relay
  • Corroded or damaged ground connections
  • Malfunctioning body control module (BCM)

Common misdiagnoses

  • Faulty rear wiper motor
  • Defective wiper switch
  • Wiring issues or shorts in the harness
  • Malfunctioning body control module (BCM)
  • Incorrectly installed or damaged relay
  • Battery or charging system problems
  • Grounding issues in the circuit

Troubleshooting steps

  1. 1. Understand the Code

    B1245 typically indicates a problem with the rear wiper motor relay circuit, specifically that there is a short to battery voltage

  2. 2. Visual Inspection

    Check Wiring and Connectors: Inspect the wiring harness and connectors related to the rear wiper motor and relay for any signs of damage, corrosion, or loose connections

  3. 3. Look for Shorts

    Check for any exposed wires that may be touching the vehicle chassis or other components, which could cause a short circuit

  4. 4. Check the Relay

    Test the Relay: Remove the rear wiper motor relay and test it using a multimeter. Check for continuity and ensure it operates correctly when energized

  5. 5. Replace if Necessary

    If the relay is faulty, replace it with a new one

  6. 6. Inspect the Rear Wiper Motor

    Test the Motor: Disconnect the rear wiper motor and test it separately to see if it operates correctly when powered directly

  7. 7. Check for Ground Issues

    Ensure that the motor has a good ground connection

  8. 8. Check for Short Circuits

    Use a Multimeter: With the vehicle off, use a multimeter to check for continuity between the wiper motor circuit and the battery positive terminal. A reading indicates a short

  9. 9. Trace the Circuit

    If a short is found, trace the wiring back to locate the source of the short

  10. 10. Inspect the Fuse

    Check the Fuse: Inspect the fuse associated with the rear wiper motor circuit. If it is blown, replace it and see if the issue persists

  11. 11. Look for Overcurrent

    If the fuse blows again, it may indicate a deeper issue, such as a short circuit

  12. 12. Scan for Additional Codes

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

  13. 13. Consult Wiring Diagrams

    Refer to Service Manuals: Use wiring diagrams specific to your vehicle model to understand the circuit layout and identify potential problem areas

  14. 14. Professional Help

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or automotive technician who can perform more advanced diagnostics

  15. 15. Clear the Code

    After repairs, clear the trouble code 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 B1245 code. Always ensure safety precautions are taken when working on electrical systems in vehicles