B1816 – Wiper Rear Motor Down Relay Coil Circuit Short To Battery

The ODBII code B1816 indicates a short circuit in the rear wiper motor down relay coil circuit, meaning that the circuit is receiving power directly from the battery instead of being controlled properly by the relay.

The severity of ODBII code B1816 is typically considered moderate to severe.

Common Causes For: B1815 Wiper Rear Motor Down Relay Coil Circuit Open

• Shorted wiring or connectors
• Faulty rear wiper motor
• Defective relay
• Corroded or damaged terminals
• Malfunctioning switch
• Grounding issues

Common misdiagnosis for B1816 Wiper Rear Motor Down Relay Coil Circuit Short To Battery

• Faulty rear wiper motor
• Defective wiper switch
• Wiring harness issues
• Bad ground connection
• Malfunctioning body control module (BCM)
• Incorrectly installed or damaged relay

Common Troubleshooting Steps

The OBD-II code B1816 indicates a problem with the rear wiper motor down relay coil circuit, specifically a short to battery. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Visual Inspection:
• Check the wiring and connectors associated with the rear wiper motor and relay for any signs of damage, corrosion, or loose connections.
• Inspect the relay itself for any physical damage.
• Check the Relay:
• Test the rear wiper motor relay by swapping it with a similar relay in the fuse box (if applicable) to see if the problem persists.
• If you have a multimeter, you can also test the relay for continuity and proper operation.
• Inspect the Wiper Motor:
• Disconnect the rear wiper motor and check for any shorts in the motor itself. Use a multimeter to measure resistance across the motor terminals.
• If the motor shows a short circuit (very low resistance), it may need to be replaced.
• Check for Shorts:
• Use a multimeter to check for continuity between the relay coil circuit and the battery. A short circuit will show continuity where there shouldn’t be any.
• Inspect the wiring harness for any signs of fraying or damage that could cause a short.
• Test the Circuit:
• With the ignition on, use a multimeter to check for voltage at the relay socket. Ensure that the correct voltage is present when the rear wiper is activated.
• Check the ground connection for the rear wiper motor and relay to ensure it is secure and functioning properly.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Repair or Replace Components:
• Based on your findings, repair any damaged wiring or connectors.
• Replace the relay or rear wiper motor if they are found to be faulty.
• Clear the Codes:
• After making repairs, clear the trouble codes 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 following these steps, it may be best to consult a professional mechanic for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the B1816 code.