B1746: Mirror Passenger Horizontal Switch Circuit Open

Definition

The OBD2 code B1746 indicates an open circuit in the passenger side mirror's horizontal switch, meaning there is a malfunction preventing the switch from functioning properly

Common causes

Faulty passenger mirror switch
Open circuit in wiring harness
Corroded or damaged connectors
Faulty passenger side mirror motor
Blown fuse related to the mirror circuit
Ground connection issues

Common misdiagnoses

Faulty passenger side mirror motor
Defective mirror switch
Wiring issues or shorts in the harness
Faulty body control module (BCM)
Incorrectly diagnosed window switch problems
Issues with the driver's side mirror controls
Problems with the vehicle's electrical system or grounds

Troubleshooting steps

1. Check the Vehicle's Manual

Refer to the vehicle's service manual for specific information related to the B1746 code, including wiring diagrams and component locations
2. Visual Inspection
3. Inspect the wiring harness connected to the passenger side mirror for any signs of damage, such as fraying, corrosion, or disconnection
4. Check the connectors for any bent pins or corrosion that could affect the connection
5. Test the Switch
6. If accessible, remove the switch from the door panel and test it with a multimeter to ensure it is functioning correctly. You can check for continuity when the switch is activated
7. If the switch is faulty, replace it
8. Check the Mirror Assembly
9. Inspect the mirror assembly for any signs of damage or malfunction. If the mirror has multiple functions (e.g., heating, tilting), ensure all functions are working properly
10. If the mirror assembly is faulty, it may need to be replaced
11. Check for Short Circuits
12. Use a multimeter to check for any short circuits in the wiring. This can help identify if there is a short to ground or another circuit that could be causing the issue
13. Scan for Additional Codes
14. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues
15. Clear the Code
16. After performing any repairs or replacements, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns
17. Consult a Professional
18. If the issue persists after performing the above steps, it may be best to consult a professional mechanic or an automotive electrician for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the B1746 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Vehicle's Manual

2. Visual Inspection

3. Inspect the wiring harness connected to the passenger side mirror for any signs of damage, such as fraying, corrosion, or disconnection

4. Check the connectors for any bent pins or corrosion that could affect the connection

5. Test the Switch

6. If accessible, remove the switch from the door panel and test it with a multimeter to ensure it is functioning correctly. You can check for continuity when the switch is activated

7. If the switch is faulty, replace it

8. Check the Mirror Assembly

9. Inspect the mirror assembly for any signs of damage or malfunction. If the mirror has multiple functions (e.g., heating, tilting), ensure all functions are working properly

10. If the mirror assembly is faulty, it may need to be replaced

11. Check for Short Circuits

12. Use a multimeter to check for any short circuits in the wiring. This can help identify if there is a short to ground or another circuit that could be causing the issue

13. Scan for Additional Codes

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

15. Clear the Code

16. After performing any repairs or replacements, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

17. Consult a Professional

18. If the issue persists after performing the above steps, it may be best to consult a professional mechanic or an automotive electrician for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the B1746 code