Adjusting headlights is a task you can do yourself with basic tools in about 15 to 30 minutes per side

Most cars allow you to adjust headlight aim using screws or bolts located behind the headlight assembly or on the back of the headlight housing itself. The goal is to point the beam low enough that oncoming drivers do not see glare, but high enough that you can see the road ahead clearly. You will need a screwdriver (usually Phillips head), possibly a wrench, a level surface, and a wall or garage door to use as a reference point.

Headlights drift out of alignment over time from vibration, minor collisions, or straightforward normal wear. Some states require headlights to be aimed correctly during vehicle inspection, and misaligned headlights reduce your visibility and can blind other drivers. The adjustment is straightforward enough that you do not need a mechanic unless the headlight housing itself is damaged or the adjustment mechanism is broken.

Key Takeaways

  • Most headlight adjustments use two screws or bolts per headlight — one controls vertical aim, the other controls horizontal aim.
  • You adjust headlights on a level surface with the car parked about 25 feet from a wall or garage door, with the fuel tank at least half full.
  • The correct aim puts the brightest part of the beam slightly below the center of the headlight and slightly to the right of the oncoming traffic lane.
  • If the adjustment screws do not turn or the headlight housing is cracked, the assembly may need replacement rather than adjustment.

Locate the adjustment screws on your headlight

Open your hood and look at the back of the headlight assembly. Most vehicles have two adjustment screws per headlight — one mounted vertically (for up-and-down aim) and one mounted horizontally (for left-and-right aim). On some cars, these screws are accessible from behind the headlight. On others, you may need to remove the headlight assembly partially or access them from inside the engine bay.

Check your vehicle's owner manual for the exact location and type of screws your model uses. Some manufacturers use Phillips head screws, others use slotted screws, and a few use bolts that require a wrench. If you cannot locate the adjustment mechanism, the headlight may use an electronic leveling system (common on luxury vehicles and some newer models), which requires a mechanic or dealer to adjust.

Set up your reference point and measure the current aim

Park your car on a level surface about 25 feet from a wall, garage door, or other flat vertical surface. The car should be perpendicular to the wall — not at an angle. Make sure the fuel tank is at least half full and the car is loaded as it normally would be (with a driver inside). These conditions matter because the car's suspension settles differently depending on weight distribution.

Turn on the low-beam headlights and observe where the beam hits the wall. You should see a distinct bright area. Mark the center of this bright area with tape or a marker so you have a reference point. The correct aim is with the brightest part of the beam slightly below the center of the headlight and slightly to the right of center (in the direction of oncoming traffic in your country).

Adjust the vertical aim first

The vertical adjustment screw controls whether the beam points up or down. Turn the vertical adjustment screw clockwise to raise the beam or counterclockwise to lower it. Make small adjustments — a quarter turn at a time — and step back to observe the change on the wall. The beam should drop about 2 inches below the center of the headlight at 25 feet of distance.

If the beam is too high, oncoming drivers will see glare and your visibility will actually be worse because the light bounces off the road surface ahead of you. If the beam is too low, you will not see far enough ahead. The sweet spot is when the top edge of the bright area is just below the horizontal center line of the headlight.

Adjust the horizontal aim second

The horizontal adjustment screw controls left-and-right aim. Turn it clockwise or counterclockwise (depending on your vehicle's design) to move the beam left or right. The goal is to center the brightest part of the beam slightly to the right of the wall's center point — roughly where the right edge of an oncoming car's lane would be.

Make quarter-turn adjustments and check the wall after each one. The horizontal aim is less critical than vertical aim for safety, but it should still be roughly centered on your side of the road. Once both screws are adjusted, turn off the headlights and repeat the process for the other headlight.

Test your headlights on the road

After adjusting both headlights, drive on a dark road (or wait until evening) to confirm the aim feels correct. You should be able to see the road clearly ahead without the beam feeling too high or too low. If oncoming drivers flash their lights at you, the headlights are still too high and need further downward adjustment.

Some roads have slight slopes or curves that can make headlights appear misaligned even when they are correct. If the aim looks good on a flat, straight section of road, it is probably correct. If you are unsure, you can have a mechanic or tire shop verify the aim using a headlight aiming machine, which is more precise than the wall method.

When to replace the headlight assembly instead

If the adjustment screws do not turn, are stripped, or turn without moving the headlight, the adjustment mechanism is broken and the assembly will need replacement. If the headlight housing is cracked, fogged, or visibly damaged, replacement is usually the better option than adjustment. A cracked housing lets moisture inside, which reduces light output and can cause electrical problems.

Replacement headlight assemblies vary widely in cost depending on your vehicle — from $100 to $500 or more per side for OEM (original equipment manufacturer) parts. Aftermarket assemblies are often cheaper but may not fit as precisely or last as long. If you are not comfortable removing and installing the assembly yourself, a mechanic can do it in 30 minutes to an hour per side.

Frequently Asked Questions

How often should I adjust my headlights?

Check your headlight aim once a year or after any collision, even a minor one. Most headlights stay in alignment for years if the car is not hit, but vibration from rough roads can gradually shift the aim. If you notice oncoming drivers flashing their lights, that is a sign to check the aim when ready.

Can I adjust headlights without removing the assembly?

Yes, on most vehicles the adjustment screws are accessible from behind the headlight without removing the entire assembly. Your owner manual will show whether your model allows this. Some cars require partial removal of trim pieces or the bumper to reach the screws, but full assembly removal is rarely necessary for adjustment alone.

What if my car has LED or HID headlights?

LED and HID headlights adjust the same way as halogen headlights — using the same screws and the same wall method. The only difference is that LED and HID bulbs produce a different light pattern, so the bright area on the wall may look slightly different, but the adjustment process is identical.

Do I need special tools to adjust headlights?

Most adjustments require only a Phillips or slotted screwdriver, which you likely already have. Some vehicles use bolts instead of screws, which need a wrench. A level and tape are helpful but not essential — you can estimate the correct aim by eye if you are careful.

Will adjusting my headlights affect my warranty?

Adjusting headlights yourself does not void your vehicle warranty. The adjustment is a maintenance task, not a modification. If the adjustment mechanism itself is broken and needs replacement under warranty, the dealer will handle that separately from any adjustments you have made.