WOMS
B code body Medium severity

B1814 Wiper Rear Motor Down Relay Coil Circuit Failure

The OBD2 code B1814 indicates a failure in the rear wiper motor down relay coil circuit, which may involve issues such as an open circuit, short circuit, or a malfunctioning relay affecting the operation of the rear...

Definition

The OBD2 code B1814 indicates a failure in the rear wiper motor down relay coil circuit, which may involve issues such as an open circuit, short circuit, or a malfunctioning relay affecting the operation of the rear wiper motor

Common causes

  • Faulty rear wiper motor
  • Damaged wiring or connectors
  • Failed relay
  • Short circuit in the circuit
  • Open circuit in the circuit
  • Corroded terminals
  • Faulty body control module (BCM)

Common misdiagnoses

  • Faulty rear wiper motor
  • Bad wiper switch
  • Wiring issues or shorts in the circuit
  • Defective body control module (BCM)
  • Incorrectly diagnosed electrical connections or grounds
  • Malfunctioning relay unrelated to the rear wiper system

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the rear wiper system and the B1814 code. This will provide you with wiring diagrams and component locations

  2. 2. Visual Inspection

    Inspect the wiring and connectors related to the rear wiper motor and relay. Look for signs of damage, corrosion, or loose connections

  3. 3. Check the rear wiper motor and relay for any physical damage

  4. 4. Test the Relay

    Locate the rear wiper relay and test it. You can do this by swapping it with a similar relay in the fuse box (if applicable) or using a multimeter to check for continuity

  5. 5. If the relay is faulty, replace it

  6. 6. Check the Fuse

    Inspect the fuse associated with the rear wiper system. If the fuse is blown, replace it and see if the issue persists

  7. 7. Test the Wiper Motor

    Apply direct power to the rear wiper motor to see if it operates. If it does not work, the motor may be faulty and needs replacement

  8. 8. If the motor works, the issue may lie in the relay or wiring

  9. 9. Check for Ground Issues

    Ensure that the rear wiper motor has a good ground connection. A poor ground can cause the motor to malfunction

  10. 10. Use a multimeter to check for continuity between the motor ground and the vehicle chassis

  11. 11. Inspect the Control Switch

    Check the rear wiper control switch for proper operation. If the switch is faulty, it may not send the correct signal to the relay or motor

  12. 12. Scan for Additional Codes

    Use an OBD-II scanner to check for any additional trouble codes that may provide more context to the issue

  13. 13. Perform a Voltage Drop Test

    Use a multimeter to perform a voltage drop test on the wiring between the relay and the wiper motor. This can help identify any resistance or breaks in the circuit

  14. 14. Consult a Professional

    If you are unable to diagnose or fix the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with electrical systems.Conclusion By following these troubleshooting steps, you should be able to identify the cause of the B1814 code and take appropriate action to resolve the issue. Always ensure safety precautions are taken when working with electrical components in your vehicle