B1783 – Mirror Passenger Up Circuit Open

The ODBII code B1783 indicates an open circuit in the passenger side mirror’s “up” movement control, meaning the system is unable to receive a signal to move the mirror upward.

The severity of ODBII code B1783 is generally considered moderate.

Common Causes For: B1782 Mirror Passenger Up Circuit Failure

• Faulty passenger side mirror switch
• Damaged wiring or connectors in the mirror circuit
• Open circuit in the mirror motor
• Blown fuse related to the mirror system
• Defective passenger side mirror assembly

Common misdiagnosis for B1783 Mirror Passenger Up Circuit Open

• Faulty passenger side mirror switch
• Wiring issues or shorts in the mirror circuit
• Defective body control module (BCM)
• Malfunctioning power window switch
• Issues with the door harness or connectors
• Faulty passenger side mirror motor
• Incorrectly installed or damaged mirror assembly

Common Troubleshooting Steps

The OBD-II code B1783 indicates a problem with the passenger side mirror’s “up” circuit, specifically that there is an open circuit. This means that the electrical path for the mirror’s upward movement is interrupted. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• Visual Inspection:
• Check the wiring harness and connectors leading to the passenger side mirror for any visible damage, fraying, or corrosion.
• Inspect the mirror assembly for any signs of physical damage.
• Check Fuses:
• Locate the fuse box and check the fuses related to the power mirrors. Replace any blown fuses.
• Test the Switch:
• Use a multimeter to test the mirror control switch. Ensure that it is functioning correctly and sending power to the mirror when the “up” button is pressed.
• Check for Power and Ground:
• With the multimeter, check for voltage at the mirror connector when the switch is activated. You should see battery voltage (typically around 12V).
• Also, check for a good ground connection at the mirror connector.
• Inspect the Mirror Motor:
• If power is present at the connector but the mirror does not move, the mirror motor itself may be faulty. Test the motor by applying direct power to it to see if it operates.
• Check for Open Circuit:
• If there is no power at the mirror connector, trace the wiring back to the switch and check for continuity. Look for any breaks or shorts in the wiring.
• 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.
• Reset the Code:
• After performing repairs, clear the code using an OBD-II scanner and see if it returns after a test drive.
• Consult Wiring Diagrams:
• If the issue persists, consult the vehicle’s wiring diagrams to understand the circuit better and identify any other components that may be involved.
• Professional Help:
• If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic or an automotive electrician. By following these steps, you should be able to identify the cause of the B1783 code and take appropriate action to fix the issue.