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Engine-Codes – Generic – B1278

B1278 Code - Headlight Switch ON Position Circuit Malfunction

Quick Answer

The B1278 code indicates a malfunction in the headlight switch ON position circuit. Common causes include Faulty headlight switch, Wiring issues or shorts in the headlight circuit, Blown fuse related to the headlight circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
B1278 indicates Headlight Switch ON Position Circuit Malfunction.
Common causes
Common causes include Faulty headlight switch, Wiring issues or shorts in the headlight circuit, Blown fuse related to the headlight circuit.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code B1278 Description

The B1278 code indicates a malfunction in the headlight switch ON position circuit. This means that there is an issue with the circuit that controls the headlights being turned on in the vehicle. The headlight switch is a crucial component that allows the driver to control the headlights, which are essential for visibility and safety while driving at night or in low-light conditions.

OBDII Code B1278 - Headlight Switch ON Position Circuit Malfunction
B1278 Code - Headlight Switch ON Position Circuit Malfunction

Common Causes of B1278

  1. Faulty headlight switch
  2. Wiring issues or shorts in the headlight circuit
  3. Blown fuse related to the headlight circuit
  4. Corrosion or poor connections in the headlight switch circuit
  5. Electronic control module (ECM) failure

Symptoms of B1278

  1. Headlights not turning on when the switch is activated
  2. Headlights flickering or dimming while driving
  3. Dashboard warning light indicating a headlight issue
  4. Battery draining quickly due to headlights staying on unintentionally

How to Fix B1278

  1. Begin by diagnosing the exact cause of the B1278 code using a diagnostic scanner to pinpoint the issue within the headlight switch ON position circuit.
  2. Inspect the headlight switch for any visible signs of damage or wear. Replace the switch if necessary.
  3. Check the wiring and connections in the headlight circuit for any corrosion, damage, or loose connections. Repair or replace as needed.
  4. Test the fuses related to the headlight circuit and replace any blown fuses.
  5. If the issue persists, consult the vehicle's service manual or seek the assistance of a professional mechanic to further diagnose and repair the problem.

Cost to Fix B1278

The cost of repairing a B1278 code related to a headlight switch ON position circuit malfunction can vary depending on the exact cause of the issue and the vehicle's make and model. In general, the cost of parts for this repair can range from $50 to $200, with labor costs typically adding an additional $100 to $300. Overall, the total repair cost can range from $150 to $500. It's important to note that these are rough estimates, and actual costs may vary based on individual circumstances and the specific repair shop's rates.

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Code B1278 Information for Specific Makes

  • B1278 Acura — Headlight Switch ON Position Circuit Malfunction
  • B1278 Honda — Headlight Switch ON Position Circuit Malfunction
About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1278 Code

1. What are common symptoms of OBDII code B1278 (Headlight Switch ON Position Circuit Malfunction)?

- Common symptoms include the headlights not turning on when the switch is in the ON position, flickering headlights, or the headlights staying on even when the switch is turned off.

2. What are possible causes of OBDII code B1278?

- Possible causes include a faulty headlight switch, damaged wiring or connectors in the headlight circuit, or a malfunctioning headlight control module.

3. How can I diagnose the issue related to OBDII code B1278?

- You can use a diagnostic scanner to read the code and further investigate the headlight switch, wiring, and control module for any visible damage or irregularities.

4. Can a DIY enthusiast repair OBDII code B1278 at home?

- Repairing this code may involve replacing the headlight switch, repairing damaged wiring, or replacing the headlight control module, which can be challenging for DIY enthusiasts. Professional help may be needed.

5. Are there any quick tips to troubleshoot OBDII code B1278?

- Before conducting any repairs, check the headlight fuse, ensure the bulbs are functioning properly, and inspect the wiring for any visible damage as a quick initial troubleshooting step.

6. Is it safe to drive with OBDII code B1278 present?

- It is not recommended to drive with this code present, as malfunctioning headlights can compromise your visibility on the road, especially at night or in low-light conditions.

7. How much does it typically cost to repair OBDII code B1278?

- The cost of repairing this code can vary depending on the specific issue causing it, but it may range from $100 to $300 for parts and labor if professional assistance is required.

8. Can OBDII code B1278 be intermittent or permanent?

- This code can be intermittent, meaning the issue causing the malfunction may come and go, or it can be a permanent issue that requires immediate attention.

9. Will resetting the OBDII system clear code B1278?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing the malfunction is not addressed, the code is likely to reappear.

10. How can I prevent OBDII code B1278 from recurring in the future?

- Regularly inspecting the headlight system, ensuring proper maintenance, and addressing any issues promptly can help prevent the recurrence of OBDII code B1278.

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