WOMS
B code body Medium severity

B1817 Wiper Rear Motor Down Relay Coil Circuit Short To Ground

The OBD2 code B1817 indicates a short circuit to ground in the rear wiper motor down relay coil circuit, which can prevent the rear wiper from functioning properly

Definition

The OBD2 code B1817 indicates a short circuit to ground in the rear wiper motor down relay coil circuit, which can prevent the rear wiper from functioning properly

Common causes

  • Damaged wiring or connectors
  • Short circuit in the relay coil circuit
  • Faulty rear wiper motor
  • Defective relay
  • Corroded or loose connections
  • Water intrusion or moisture in the circuit
  • Faulty body control module (BCM)

Common misdiagnoses

  • Faulty rear wiper motor
  • Damaged wiring or connectors
  • Faulty wiper switch
  • Malfunctioning body control module (BCM)
  • Incorrectly installed or defective relay
  • Grounding issues unrelated to the relay circuit
  • Short circuits in adjacent circuits or components

Troubleshooting steps

  1. 1. Visual Inspection

    Wiring and Connectors: Inspect the wiring harness and connectors related to the rear wiper motor and relay. Look for any signs of damage, fraying, or corrosion

  2. 2. Ground Connections

    Check the ground connections for the rear wiper motor and relay. Ensure they are clean and secure

  3. 3. 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

  4. 4. Replace if Necessary

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

  5. 5. Inspect the Rear Wiper Motor

    Motor Functionality: Test the rear wiper motor by applying direct power to it. If it does not operate, the motor may be faulty and require replacement

  6. 6. Check for Shorts

    Inspect the motor for any internal shorts that could cause a short to ground

  7. 7. Check for Shorts in the Wiring

    Continuity Test: Use a multimeter to check for continuity in the wiring between the relay and the rear wiper motor. Look for any shorts to ground

  8. 8. Inspect for Pinched Wires

    Look for any pinched or damaged wires that could be causing a short circuit

  9. 9. 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 to the issue

  10. 10. Inspect the Fuse

    Check the Fuse: Locate the fuse for the rear wiper motor and check if it is blown. Replace it if necessary, but also investigate the cause of the blown fuse

  11. 11. Test the Circuit

    Voltage Test: With the ignition on, use a multimeter to check for voltage at the relay and motor terminals. Ensure that the correct voltage is present

  12. 12. Ground Test

    Check the ground side of the circuit to ensure it is functioning properly

  13. 13. Consult Wiring Diagrams

    Refer to Service Manual: Use the vehicle’s service manual to refer to wiring diagrams for the rear wiper motor circuit. This can help identify any other components that may be involved

  14. 14. Professional Diagnosis

    Seek 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.Conclusion By following these troubleshooting steps, you should be able to identify and resolve the issue related to the OBD-II code B1817. Always ensure safety precautions are taken when working with electrical components in a vehicle