B1810 – Lamp Backup Switch Input Circuit Failure

The ODBII code B1810 indicates a failure in the backup lamp switch input circuit, which may affect the operation of the reverse lights in a vehicle.

The severity of ODBII code B1810 is generally considered moderate.

Common Causes For: B1809 Lamp Tail Output Circuit Short To Ground

• Faulty backup lamp switch
• Damaged wiring or connectors
• Short circuit in the circuit
• Open circuit in the circuit
• Corroded terminals
• Faulty body control module (BCM)
• Poor ground connection

Common misdiagnosis for B1810 Lamp Backup Switch Input Circuit Failure

• Faulty backup lamp bulbs
• Defective backup lamp relay
• Wiring issues or shorts in the circuit
• Malfunctioning transmission range sensor
• Faulty body control module (BCM)
• Incorrectly installed or damaged connectors
• Issues with the vehicle’s fuse box or blown fuses

Common Troubleshooting Steps

The OBD-II code B1810 indicates a “Lamp Backup Switch Input Circuit Failure.” This code is typically associated with issues in the backup lamp switch circuit, which is responsible for signaling when the vehicle is in reverse and activating the reverse lights. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information related to the B1810 code, including wiring diagrams and component locations.
• Visual Inspection: Inspect the wiring and connectors associated with the backup lamp switch. Look for signs of damage, corrosion, or loose connections.
• Check the backup lamp bulbs to ensure they are functioning properly.
• Test the Backup Lamp Switch: Locate the backup lamp switch, which is usually mounted on the transmission.
• Use a multimeter to test the switch for continuity. When the switch is activated (in reverse), it should show continuity. If it does not, the switch may be faulty and needs replacement.
• Check the Circuit: Inspect the wiring harness for any breaks or shorts. Use a multimeter to check for continuity in the wiring between the switch and the power source.
• Ensure that there are no shorts to ground or open circuits.
• Inspect the Fuse: Check the fuse related to the backup lights and the backup lamp switch circuit. If the fuse is blown, replace it and see if the code returns.
• 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.
• Check the Body Control Module (BCM): If the backup lamp switch and wiring are functioning correctly, the issue may lie within the BCM. Check for any faults or issues with the BCM that could affect the backup lamp circuit.
• Clear the Code and Test Drive: After performing the necessary repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after following these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1810 code.