7 Reasons Led Headlights Only Work On High Beam

Headlights can malfunction in numerous different ways. It’s vital to notice the type of failure you’re experiencing if you discover that your led headlights only work on high beams. We go over seven potential causes for this below and the associated conditions.

How Do Car Headlights Work?

Headlights were flames fuelled by acetylene gas that was blazing behind glass lenses. Most headlight systems are simple and comprise standard parts, including lights, a relay, a circuit, and a switch.

Car headlight

Car headlight 

That switch turns on a relay, which then turns on your headlights. Your headlight lights and batteries are electrically connected using the relay.

Since your headlight switch engages a relay, pressing the high beam switch will turn on your high beams by activating a relay. It supplies energy to the high-beam bulb in headlight capsules with two filaments.

Simple automated headlights function using sensors to measure the amount of light outdoors. Most of these sensors are found on the car’s dashboard, and the headlights come on when the sensors determine enough darkness.

Simple, older solutions turn on the headlights at dusk and turn them off at dawn, and modern solutions use sensors to determine how much exterior light is there.

7 Reasons Led Headlights Only Work On High Beam 

Led Headlights Only Work On High Beam 

A Corroded Headlight Socket

High beams are brighter than low beams and allow for more excellent distant seeing. Low beam lights are standard lights that are not any brighter and won’t cause blindness.

A bulb fitted into an electrical connection socket is the headlight on many automobiles. The headlight socket may corrode if these connectors are sloppy, the circuit has poor ground, or moisture has entered.

A headlight that blinks repeatedly or goes out once and stays out could result from this initial cause.

Compromise In Headlight Wiring

Wiring damage is the primary source of short circuits. While chafed, broken wire merely prevents electrical flow. Particularly at the headlight bulbs, weak or corroded connections might become overheated and melt.

Car wiring damage

Car wiring damage  

For your safety, we recommend getting the wiring examined by a licensed professional if it may cause your headlight issues.

Broken Headlight Switch

Since the headlight switch is located inside the car and is well-protected, it rarely fails. However, a malfunctioning headlight switch can cause issues.

You may burn out the headlight switch because you travel a lot, particularly at night when you always have to alternate between high and low beams. The button may wear out and stop turning on the headlights altogether, or it could become stuck in the high beam setting.

Headlight switch

Headlight switch 

Bad Headlight Fuse Or Relay

Your car’s headlights are protected against excessive electricity by a fuse that is part of the circuit. The headlight switch will be shielded from the high current drawn by the high-beam headlights by a headlight relay as well.

A short circuit will cause the fuse to explode, but an accessory drawing off could also cause it to do so. There will be no headlights at all if the fuse blows. However, switching between high and low beams will only be possible if the relay malfunctions.

Headlight Bulb Blown

The main reason why LED headlights only function on high beams is this. Depending on the type of bulb you purchase, car bulbs typically last between 450 and 11,000+ hours.

Due to the presence of two separate filaments – one for the high beam and one for the low beam—in the bulb, most “blown” car headlights continue to function brightly. Because it is utilized the most—unless you’re one of those who always drive with their high beams on—the low beam is most frequently the first to go wrong and explode.

Ineffective HID generator

High-intensity discharge (HID) headlights have an additional component. When the bulb is turned on, the HID generator raises the voltage to 30,000 V, where it stabilizes. The lamp won’t illuminate if the generator breaks down.

Foggy Headlights

If your car’s led headlights only function on high beams, headlight fogging may be a problem. Due to exposure to the sun’s ultraviolet light, polycarbonate has undergone a fundamental chemical shift.

It emits caustic exhaust. It’s challenging to see because the diffused light needs to project more effectively.

Led Headlights Only Work On High Beam: How To Fix It?

Led Headlights Only Work On High Beam How To Fix It

Clean Headlight

You don’t need many supplies to clean your car’s headlights. A soft cloth, water, and dish soap will work well for filth.

Most of the time, it’s not dirt, but sun damage and exposure to older cars’ plastic headlight lenses make them yellow or frosted. If you have recently purchased a used automobile or an old car, vinegar is a great technique to clean and repair the headlights.

Cleaned headlight

Cleaned headlight 

A headlight cleaning kit costing $10 comes with a container of high-grade rubbing compound. Removing the old coating without replacing it will hasten the deterioration.

Monitor For Voltage Drops

The unwanted resistant circuit is a typical reason for poor headlamp performance. Checking for voltage drops in a course is a practical approach to identifying high resistance since undesirable resistance results in voltage dips.

While the actual inspection is straightforward, some models may make it challenging to access switches and connectors for testing. An ideal voltage drop would be around 200 mV.

You might require the diagram for your specific vehicle’s make and model. You can find this diagram in your car’s repair manual.

Replace The Bulb

Based on how much of your driving is at night, if you log 15,000 miles a year, you could need to change a lightbulb after 5 or 6 years. Examine the electrical connector behind the headlight before changing the lightbulb to the non-working one.

Remember not to use your fingers to touch the new halogen bulb’s glass. A rusted connection or a wiring issue could cause the bulb not to light up.

Some HID headlights have an integrated bulb and ignitor. Thus you must change both. Check your manual to find out if your car has one of them. Finding out which HID you should change the headlamp requires more investigation because specific HID headlight applications use different bulbs and ignitors.


Having led headlights only work on high beams is a common issue, so if it affects your automobile, don’t be concerned. It’s crucial to determine the source so your car can be fixed. There are a few possibilities, but the problem is most likely an electrical one or a mechanical one with the bulbs. Calling an expert is essential because you cannot handle this problem yourself, and it needs to be addressed as soon as feasible.

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