WOMS
B code body Medium severity

B1784 Mirror Passenger Up Circuit Short To Battery

The OBD2 code B1784 indicates a short circuit in the passenger side mirror's "up" control circuit, causing it to be continuously powered as if it is connected directly to the battery

Definition

The OBD2 code B1784 indicates a short circuit in the passenger side mirror's "up" control circuit, causing it to be continuously powered as if it is connected directly to the battery

Common causes

  • Shorted wiring or connectors in the passenger mirror circuit
  • Faulty passenger side mirror switch
  • Defective passenger side mirror motor
  • Corroded or damaged electrical connections
  • Malfunctioning body control module (BCM)

Common misdiagnoses

  • Faulty passenger side mirror switch
  • Damaged wiring harness
  • Shorted wiring in the door panel
  • Malfunctioning body control module (BCM)
  • Defective passenger side mirror motor
  • Issues with the vehicle's electrical system
  • Incorrectly installed aftermarket accessories

Troubleshooting steps

  1. 1. Visual Inspection

    Wiring and Connectors: Check the wiring harness and connectors leading to the passenger side mirror. Look for any signs of damage, fraying, or corrosion

  2. 2. Mirror Assembly

    Inspect the mirror assembly itself for any physical damage or signs of water intrusion

  3. 3. Check for Short Circuits

    Multimeter Testing: Use a multimeter to check for continuity in the mirror's wiring. Disconnect the mirror connector and test the wires for continuity to ground or battery voltage

  4. 4. Resistance Check

    Measure the resistance of the mirror motor. If it is too low (indicating a short), the motor may need to be replaced

  5. 5. Inspect the Switch

    Switch Functionality: Test the mirror control switch to ensure it is functioning correctly. A faulty switch can send incorrect signals to the mirror motor

  6. 6. Wiring to Switch

    Check the wiring from the switch to the mirror for any shorts or damage

  7. 7. Check the Power Supply

    Voltage Check: With the mirror connector still disconnected, check for proper voltage at the connector when the switch is activated. You should see battery voltage when the switch is pressed

  8. 8. Ground Connection

    Ensure that the ground connection for the mirror is solid and free of corrosion

  9. 9. Scan for Additional Codes

    Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  10. 10. Inspect the Body Control Module (BCM)

    BCM Functionality: If all wiring and components appear to be in good condition, the issue may lie within the BCM. Check for any software updates or known issues with the BCM related to mirror control

  11. 11. Repair or Replace Components

    Repair Wiring: If any damaged wiring or connectors are found, repair or replace them as necessary

  12. 12. Replace Faulty Components

    If the mirror motor, switch, or BCM is determined to be faulty, replace the component

  13. 13. Clear Codes and Test

    After making repairs, clear the trouble codes using the OBD-II scanner and test the mirror operation to see if the issue is resolved

  14. 14. Professional Help

    If you are unable to diagnose or fix the issue, consider seeking help from a professional mechanic or an automotive electrician. By following these steps, you should be able to identify and resolve the issue related to the B1784 code