What Is a Headlight Fuse?

Fuses safeguard the electrical system of your car. A single fuse protects each circuit in your car. Each of the headlight circuits in your car is protected by a headlight fuse. These fuses are housed in a fuse box, which is often positioned on the firewall or behind the dash. It is generally straightforward to access and contains a schematic of which fuse connects where.

Types of Headlight Fuse

Headlight fuses are classified into two types:

  • Standard headlight fuses
  • High-beam headlight fuses

The standard headlight fuse is generally located under the hood, which protects the headlight, taillight, and brake light circuits. And the high-beam headlight fuse is generally placed under the dash that protects the high-beam circuits.

Headlight Fuse

The Function of a Headlight Fuse

A headlight fuse allows electrical current to pass through it to the headlight. If the current running through the headlight circuit surpasses the fuse’s limit, the fuse will “break,” cutting off the electrical flow. This keeps the headlight circuit from becoming overloaded, which might damage the switch, the bulbs, or the wiring.

Headlight fuses are typically color-coded to make them easier to recognize. The colors will vary based on your vehicle’s make and model, but they are commonly white, blue, green, or yellow. Low beam headlight fuses are usually blue or white, while high beam headlight fuses are usually yellow or green.

How to Check if Your Headlight Fuse is Faulty?

If the wire within the fuse is burnt out, the fuse is faulty. If the wire appears to be in good condition, use an electrical meter or a test light to check for continuity. If the fuse has continuity, it does not always mean that it is operating well.

You can also test with a multimeter. Touch the probes to the fuse’s two ends to test it. If the multimeter reading is zero ohms or very low, the fuse is fine. If the multimeter reads “infinity,” the fuse is not operational.

Symptoms of a Bad Fuse

The most common sign of a faulty headlight fuse is that the headlights do not turn on. Other symptoms may include flickering or fading headlights and headlight bulbs blowing out frequently.

Most headlight systems typically include a relay that regulates the power between low and high beam headlights. If this relay fails, the fuse may route the power to the high beams but not the low beams.

Front Headlight Fuse

How to Install a New Fuse?

Fixing a headlight fuse is a relatively simple and straightforward procedure that will take minimal time and effort to complete, and it will save you money. It usually takes three steps.

Step 1

See the owner’s manual to locate the fuse box in your car. It is usually located near the car battery, under the dashboard, or in the trunk. Identify the fuse box by looking for the headlight symbols. If your car does not have the headlight symbols and your owner’s manual is missing, visit the automobile manufacturer’s website to see if one for your make and model is available for free.

Step 2

To access the fuses, remove or unscrew the top of the fuse box. Remove the old fuse by firmly holding it between two fingers and pushing it upwards or outwards. If it is resistive, wiggle it side to side instead of forcing it. Never touch the wires inside the box. Take the fuse to an auto parts store for comparison and buy one with the same amperage.

Step 3

Replace the old fuse with the new fuse and insert it into the existing outlet. Line up the fuse prongs and firmly press them in. To avoid damaging the fuse, do not press too hard. They will not fit if the fuses are not correctly aligned. Use your headlights to check for proper alignment.

Your electrical system may be malfunctioning if the replacement fuse blows right away. A loose or broken wire might cause this. Check that all of the cables leading to the headlight are secure. If the headlights still do not work, you may need to change the relay switch or the wiring, depending on the issue.

Final Notes

You should get a fuse that meets the specifications of your car. Most modern cars use 20 to 30 amp fuses. A voltmeter is usually a good idea to keep in the car. It allows you to check the voltage of your car’s battery when the engine is running (it should be about 13 to 14 V) and when it is turned off (around 12 V).

If the voltage is less than 12 V, your fuse may break. You can get a typical voltmeter from auto parts stores for $20 to $30.

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