B1813 – Lamp Backup Switch Input Circuit Short To Ground

The ODBII 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.

The severity of ODBII code B1813 is generally considered moderate.

Common Causes For: B1812 Lamp Backup Switch Input Circuit Short To Battery

• 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 misdiagnosis for B1813 Lamp Backup Switch Input Circuit Short To Ground

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

Common Troubleshooting Steps

The OBD-II code B1813 indicates a problem with the backup lamp switch input circuit, specifically a short to ground. This code is often associated with issues in the vehicle’s backup light system. Here are some common troubleshooting steps to diagnose and resolve the issue:

• 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.
• **Backup Lamp Switch: Check the backup lamp switch itself for any visible damage or wear.
• 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.
• **Inspect Ground Points: Ensure that all ground points related to the backup lamp circuit are clean and secure.
• 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).
• **Replace if Necessary: If the switch is faulty, replace it.
• Check the Backup Lamps: **Bulb Condition: Inspect the backup light bulbs to ensure they are not blown or shorted.
• **Wiring to Bulbs: Check the wiring leading to the backup lamps for any signs of damage or shorts.
• 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.
• Inspect Related Components: **Body Control Module (BCM): If applicable, check the BCM for any faults or issues that could affect the backup lamp circuit.
• **Fuses: Inspect the fuses related to the backup lights and the circuit to ensure they are intact.
• Repair or Replace Faulty Components: Based on your findings, repair or replace any damaged wiring, connectors, or components.
• 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.
• Consult Service Manual: If the issue persists, consult the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the backup lamp circuit.
• 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.