WOMS
B code body Medium severity

B1785 Mirror Passenger Up Circuit Short To Ground

The OBD2 code B1785 indicates a fault in the passenger side mirror's "up" movement circuit, specifically a short to ground, which means there is an unintended connection to the vehicle's ground, preventing the mirror...

Definition

The OBD2 code B1785 indicates a fault in the passenger side mirror's "up" movement circuit, specifically a short to ground, which means there is an unintended connection to the vehicle's ground, preventing the mirror from functioning properly

Common causes

  • Damaged wiring or connectors in the mirror circuit
  • Shorted or faulty mirror switch
  • Malfunctioning power mirror motor
  • Corroded or loose electrical connections
  • Faulty body control module (BCM)
  • Water intrusion or moisture in the electrical components

Common misdiagnoses

  • Faulty passenger side mirror switch
  • Damaged wiring harness
  • Shorted wiring in the door panel
  • Defective body control module (BCM)
  • Malfunctioning power window switch
  • Incorrectly installed or faulty mirror assembly
  • Issues with the vehicle's electrical system or grounding points

Troubleshooting steps

  1. 1. Visual Inspection

  2. 2. Check the wiring harness and connectors associated with the passenger side mirror. Look for any signs of damage, fraying, or corrosion

  3. 3. Inspect the mirror assembly for any physical damage that could affect the wiring

  4. 4. Check for Shorts

  5. 5. Use a multimeter to check for continuity in the wiring. Disconnect the mirror connector and test the wires for continuity to ground. If you find continuity, there may be a short in the wiring

  6. 6. Inspect the wiring for any areas where it may be pinched or rubbing against metal surfaces

  7. 7. Test the Mirror Motor

  8. 8. If the wiring appears intact, test the mirror motor itself. You can do this by applying direct power to the motor to see if it operates correctly

  9. 9. If the motor does not work when powered directly, it may need to be replaced

  10. 10. Check the Switch

  11. 11. Inspect the mirror control switch for proper operation. A faulty switch can cause incorrect signals to be sent to the mirror motor

  12. 12. Test the switch for continuity and proper function. If it’s defective, replace it

  13. 13. Scan for Additional Codes

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

  15. 15. Inspect Ground Connections

  16. 16. Ensure that all ground connections related to the mirror and the control circuit are clean and secure. A poor ground can cause erratic behavior and false codes

  17. 17. Check for Water Intrusion

  18. 18. Water can sometimes enter the mirror assembly or wiring harness, causing shorts. Inspect for any signs of moisture or corrosion

  19. 19. Repair or Replace Components

  20. 20. Based on your findings, repair any damaged wiring or connectors. If the mirror motor or switch is faulty, replace them as necessary

  21. 21. Clear Codes and Test Drive

  22. 22. After making repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  23. 23. If the issue persists, consult the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the mirror circuit. By following these steps, you should be able to identify and resolve the issue causing the B1785 code. If you're not comfortable performing these diagnostics, consider seeking assistance from a professional mechanic