WOMS
B code body Medium severity

B1813 Lamp Backup Switch Input Circuit Short To Ground

The OBD2 code B1813 indicates a malfunction in the backup lamp switch input circuit, specifically that there is a short to ground, which means the circuit is unintentionally connected to the ground, causing improper...

Definition

The OBD2 code B1813 indicates a malfunction in the backup lamp switch input circuit, specifically that there is a short to ground, which means the circuit is unintentionally connected to the ground, causing improper operation of the backup lights

Common causes

  • Shorted wiring or connectors in the backup lamp circuit
  • Faulty backup lamp switch
  • Damaged or corroded connectors
  • Grounding issues in the circuit
  • Malfunctioning body control module (BCM)
  • Incorrectly installed or damaged aftermarket accessories

Common misdiagnoses

  • Faulty backup lamp switch
  • Wiring harness issues
  • Shorted wiring
  • Faulty body control module (BCM)
  • Defective backup lamps
  • Grounding issues
  • Corroded connectors

Troubleshooting steps

  1. 1. Visual Inspection

    Wiring and Connectors: Inspect the wiring harness and connectors related to the backup lamp switch. Look for frayed wires, corrosion, or loose connections

  2. 2. Backup Lamp Switch

    Check the backup lamp switch itself for any visible damage or wear

  3. 3. Check for Short Circuits

    Multimeter Testing: Use a multimeter to check for continuity in the backup lamp switch circuit. Disconnect the switch and measure resistance between the switch terminals and ground. A low resistance reading indicates a short to ground

  4. 4. Inspect Ground Points

    Ensure that all ground points related to the backup lamp circuit are clean and secure

  5. 5. Test the Backup Lamp Switch

    Functionality Test: With the switch disconnected, test it for proper operation. You can do this by checking for continuity when the switch is activated (in reverse)

  6. 6. Replace if Necessary

    If the switch is faulty, replace it

  7. 7. Check the Backup Lamps

    Bulb Condition: Inspect the backup light bulbs to ensure they are not blown or shorted

  8. 8. Wiring to Bulbs

    Check the wiring leading to the backup lamps for any signs of damage or shorts

  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 to the issue

  10. 10. Inspect Related Components

    Body Control Module (BCM): If applicable, check the BCM for any faults or issues that could affect the backup lamp circuit

  11. 11. Fuses

    Inspect the fuses related to the backup lights and the circuit to ensure they are intact

  12. 12. Repair or Replace Faulty Components

    Based on your findings, repair or replace any damaged wiring, connectors, or components

  13. 13. Clear Codes and Test Drive

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

  14. 14. Seek Professional Help

    If you are unable to resolve the issue, consider seeking assistance from a qualified mechanic or automotive technician. By following these steps, you should be able to identify and resolve the issue causing the B1813 code