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

Definition

The OBD2 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

Common causes

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

Common misdiagnoses

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

Troubleshooting steps

1. Visual Inspection
2. Check the wiring and connectors associated with the rear wiper motor and relay for any signs of damage, corrosion, or loose connections
3. Inspect the relay itself for any physical damage
4. Check the Relay
5. 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
6. If you have a multimeter, you can also test the relay for continuity and proper operation
7. Inspect the Wiper Motor
8. Disconnect the rear wiper motor and check for any shorts in the motor itself. Use a multimeter to measure resistance across the motor terminals
9. If the motor shows a short circuit (very low resistance), it may need to be replaced
10. Check for Shorts
11. 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
12. Inspect the wiring harness for any signs of fraying or damage that could cause a short
13. Test the Circuit
14. 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
15. Check the ground connection for the rear wiper motor and relay to ensure it is secure and functioning properly
16. Scan for Additional Codes
17. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues
18. Repair or Replace Components
19. Based on your findings, repair any damaged wiring or connectors
20. Replace the relay or rear wiper motor if they are found to be faulty
21. Clear the Codes
22. 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
23. Consult a Professional
24. 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

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Visual Inspection

2. Check the wiring and connectors associated with the rear wiper motor and relay for any signs of damage, corrosion, or loose connections

3. Inspect the relay itself for any physical damage

4. Check the Relay

5. 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

6. If you have a multimeter, you can also test the relay for continuity and proper operation

7. Inspect the Wiper Motor

8. Disconnect the rear wiper motor and check for any shorts in the motor itself. Use a multimeter to measure resistance across the motor terminals

9. If the motor shows a short circuit (very low resistance), it may need to be replaced

10. Check for Shorts

11. 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

12. Inspect the wiring harness for any signs of fraying or damage that could cause a short

13. Test the Circuit

14. 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

15. Check the ground connection for the rear wiper motor and relay to ensure it is secure and functioning properly

16. Scan for Additional Codes

17. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

18. Repair or Replace Components

19. Based on your findings, repair any damaged wiring or connectors

20. Replace the relay or rear wiper motor if they are found to be faulty

21. Clear the Codes

22. 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

23. Consult a Professional

24. 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