B1748 – Mirror Passenger Horizontal Switch Circuit Short To Ground

The ODBII code B1748 indicates a short circuit to ground in the passenger side mirror’s horizontal switch circuit, which affects the operation of the mirror adjustment.

The severity of ODBII code B1748 is moderate.

Common Causes For: B1747 Mirror Passenger Horizontal Switch Circuit Short To Battery

• Damaged wiring or connectors in the mirror switch circuit.
• Shorted or faulty mirror switch.
• Corroded or loose connections.
• Water intrusion or moisture in the switch or wiring.
• Faulty passenger side mirror motor.

Common misdiagnosis for B1748 Mirror Passenger Horizontal Switch Circuit Short To Ground

• Faulty passenger side mirror switch
• Damaged wiring or connectors in the mirror circuit
• Malfunctioning body control module (BCM)
• Short circuit in the vehicle’s electrical system
• Issues with the driver side mirror switch
• Faulty passenger side mirror motor
• Incorrectly installed or aftermarket mirror components

Common Troubleshooting Steps

When dealing with an OBD-II code B1748, which indicates a “Mirror Passenger Horizontal Switch Circuit Short To Ground,” you can follow these common troubleshooting steps:

• Verify the Code: Use an OBD-II scanner to confirm the presence of the B1748 code. Clear the code and see if it returns after a short drive.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors associated with the passenger side mirror switch. Look for any signs of damage, fraying, or corrosion.
• **Connector Check: Ensure that all connectors are securely attached and free of dirt or moisture.
• Test the Switch: **Switch Functionality: Use a multimeter to test the passenger mirror switch for proper operation. Check for continuity in the switch when it is activated.
• **Resistance Check: Measure the resistance across the switch terminals to ensure it is within specifications.
• Check for Shorts to Ground: **Wiring Inspection: Inspect the wiring for any shorts to ground. Use a multimeter to check for continuity between the switch wires and ground.
• **Pinpoint Testing: Disconnect the switch and check the wiring harness for continuity to ground. If there is continuity, there may be a short in the wiring.
• Inspect the Mirror Assembly: **Motor and Components: If the wiring and switch are fine, inspect the mirror assembly itself. Check the motor and any internal components for shorts or failures.
• **Connector Check: Ensure that the connectors at the mirror assembly are secure and free from corrosion.
• Check for Related Codes: Look for any other related trouble codes that may provide additional context or indicate a broader issue with the vehicle’s electrical system.
• Repair or Replace Components: Based on your findings, repair any damaged wiring or connectors. If the switch or mirror motor is faulty, consider replacing them.
• Clear Codes and Test Drive: After making repairs, clear the codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: If the issue persists, consult the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the mirror switch circuit.
• Seek Professional Help: If you are unable to resolve the issue, consider seeking assistance from a professional mechanic or automotive technician who has experience with electrical systems. By following these steps, you should be able to diagnose and potentially resolve the issue related to the B1748 code.