B1746 – Mirror Passenger Horizontal Switch Circuit Open

The ODBII 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.

The severity of ODBII code B1746 is generally considered moderate.

Common Causes For: B1745 Mirror Passenger Horizontal Switch Circuit Failure

• 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 misdiagnosis for B1746 Mirror Passenger Horizontal Switch Circuit Open

• 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

Common Troubleshooting Steps

The OBD-II code B1746 refers to an issue with the passenger side mirror’s horizontal switch circuit being open. This can indicate a problem with the wiring, the switch itself, or the mirror assembly. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• 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.
• Visual Inspection:
• Inspect the wiring harness connected to the passenger side mirror for any signs of damage, such as fraying, corrosion, or disconnection.
• Check the connectors for any bent pins or corrosion that could affect the connection.
• Test the Switch:
• 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.
• If the switch is faulty, replace it.
• Check the Mirror Assembly:
• 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.
• If the mirror assembly is faulty, it may need to be replaced.
• Check for Short Circuits:
• 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.
• 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.
• Clear the Code:
• 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.
• Consult a Professional:
• 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.