B1814 – Wiper Rear Motor Down Relay Coil Circuit Failure

The ODBII 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.

The severity of ODBII code B1814 is generally considered moderate.

Common Causes For: B1813 Lamp Backup Switch Input Circuit Short To Ground

• 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 misdiagnosis for B1814 Wiper Rear Motor Down Relay Coil Circuit Failure

• 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

Common Troubleshooting Steps

The OBD-II code B1814 indicates a problem with the rear wiper motor down relay coil circuit. This code can be triggered by various issues, including electrical faults, component failures, or wiring problems. 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 regarding the rear wiper system and the B1814 code. This will provide you with wiring diagrams and component locations.
• Visual Inspection: Inspect the wiring and connectors related to the rear wiper motor and relay. Look for signs of damage, corrosion, or loose connections.
• Check the rear wiper motor and relay for any physical damage.
• 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.
• If the relay is faulty, replace it.
• 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.
• 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.
• If the motor works, the issue may lie in the relay or wiring.
• Check for Ground Issues: Ensure that the rear wiper motor has a good ground connection. A poor ground can cause the motor to malfunction.
• Use a multimeter to check for continuity between the motor ground and the vehicle chassis.
• 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.
• Scan for Additional Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context to the issue.
• 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.
• 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.