B1795: Lamp Headlamp Low-Beam Circuit Open

Definition

The OBD2 code B1795 indicates that there is an open circuit in the low-beam headlamp circuit, meaning the system is not detecting the low-beam headlamp as functioning properly

Common causes

Open circuit in the low-beam headlamp wiring
Faulty low-beam headlamp bulb
Defective headlamp relay
Poor ground connection
Damaged or corroded connectors
Faulty body control module (BCM)
Blown fuse in the headlamp circuit

Common misdiagnoses

Faulty headlight bulb
Bad headlight relay
Damaged wiring or connectors
Faulty body control module (BCM)
Incorrectly installed headlight assembly
Malfunctioning switch or control stalk
Grounding issues
Faulty fuse or fuse box issues

Troubleshooting steps

1. Visual Inspection
2. Check the headlamp assembly for any visible damage or corrosion
3. Inspect the wiring harness and connectors for frayed wires, loose connections, or corrosion
4. Ensure that the headlamp bulbs are properly seated in their sockets
5. Check the Headlamp Bulbs
6. Remove the low-beam headlamp bulbs and test them with a multimeter or replace them with known good bulbs to rule out a bulb failure
7. Test the Headlamp Circuit
8. Use a multimeter to check for voltage at the headlamp connector while the low beams are turned on. You should see battery voltage (typically around 12V)
9. If there is no voltage, trace the wiring back to the fuse box and check for continuity
10. Inspect Fuses and Relays
11. Check the fuse associated with the low-beam headlamps. If it is blown, replace it and see if the problem persists
12. Test the relay for the low-beam headlamps (if applicable) to ensure it is functioning correctly
13. Check Ground Connections
14. Ensure that the ground connection for the headlamp circuit is secure and free of corrosion. A poor ground can cause an open circuit
15. Scan for Additional Codes
16. Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue
17. Inspect the Body Control Module (BCM)
18. If all other components check out, the issue may lie within the BCM or the wiring leading to it. Check for any software updates or known issues with the BCM
19. Consult Wiring Diagrams
20. Refer to the vehicle’s wiring diagrams to trace the circuit and identify any other components that may be involved in the low-beam circuit
21. Perform a Continuity Test
22. With the vehicle off, perform a continuity test on the wiring from the headlamp connector back to the BCM or fuse box to ensure there are no breaks in the wire
23. Professional Diagnosis
24. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the B1795 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Visual Inspection

2. Check the headlamp assembly for any visible damage or corrosion

3. Inspect the wiring harness and connectors for frayed wires, loose connections, or corrosion

4. Ensure that the headlamp bulbs are properly seated in their sockets

5. Check the Headlamp Bulbs

6. Remove the low-beam headlamp bulbs and test them with a multimeter or replace them with known good bulbs to rule out a bulb failure

7. Test the Headlamp Circuit

8. Use a multimeter to check for voltage at the headlamp connector while the low beams are turned on. You should see battery voltage (typically around 12V)

9. If there is no voltage, trace the wiring back to the fuse box and check for continuity

10. Inspect Fuses and Relays

11. Check the fuse associated with the low-beam headlamps. If it is blown, replace it and see if the problem persists

12. Test the relay for the low-beam headlamps (if applicable) to ensure it is functioning correctly

13. Check Ground Connections

14. Ensure that the ground connection for the headlamp circuit is secure and free of corrosion. A poor ground can cause an open circuit

15. Scan for Additional Codes

16. Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue

17. Inspect the Body Control Module (BCM)

18. If all other components check out, the issue may lie within the BCM or the wiring leading to it. Check for any software updates or known issues with the BCM

19. Consult Wiring Diagrams

20. Refer to the vehicle’s wiring diagrams to trace the circuit and identify any other components that may be involved in the low-beam circuit

21. Perform a Continuity Test

22. With the vehicle off, perform a continuity test on the wiring from the headlamp connector back to the BCM or fuse box to ensure there are no breaks in the wire

23. Professional Diagnosis

24. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the B1795 code