Why and when to adjust your headlights

Headlights drift out of aim over time — from hitting a pothole, a minor collision, or just the wear on suspension parts. When they point too high, you blind oncoming drivers. When they point too low, you lose sight of the road ahead. Most states require headlights to be aimed correctly, and police can ticket you for headlights that are dangerously misaligned.

You should check your aim if oncoming drivers flash their lights at you, if you notice the beam pattern looks uneven on a wall at night, or if you've had recent work done on the front end. Many people adjust headlights once a year or after any collision, even a minor one.

Key Takeaways

  • You can adjust most modern headlights by turning screws or bolts behind the headlight housing, usually accessible from inside the engine bay.
  • The correct aim puts the light beam slightly below the center of oncoming traffic, so you see far ahead without blinding other drivers.
  • A wall or garage door and a level, dark surface are all you need to check aim at home — no special tools required for the test itself.
  • If your headlights are sealed units or if adjustment screws are not accessible, a shop can aim them with a headlight aiming machine in about 30 minutes.

How to find the adjustment screws

Open your hood and look directly behind each headlight. You will see the back of the headlight housing. Most headlights have two adjustment screws or bolts — one controls vertical aim (up and down), and one controls horizontal aim (left and right). On some vehicles, the screws are on the top and side of the housing. On others, they are on the back.

Check your owner's manual for the exact location on your vehicle — it will show you which screw does what. If the manual is not available, take a photo of the back of the headlight and search online for "[your year, make, model] headlight adjustment" to find diagrams. Some vehicles have plastic adjustment wheels instead of screws; these turn by hand without tools.

If you cannot locate adjustment screws or if the housing is sealed, your headlights may not be user-adjustable. Many newer vehicles use sealed LED or HID headlights that require a shop visit.

Setting up a test surface

You need a flat wall or garage door and a level, dark area to see the beam pattern clearly. Park your car about 25 feet from the wall, on level ground, with the car pointing straight at the wall. Make sure the car is not tilted — if one side is higher than the other, the test will be inaccurate. Turn off the engine and turn on the low-beam headlights only.

Let your eyes adjust to the dark for a minute so you can see the beam pattern clearly. The beam should form a distinct shape on the wall — you will see where the light is brightest and where it fades. This pattern tells you whether the headlights are aimed too high, too low, or to the side.

Understanding the correct beam pattern

The correct aim puts the brightest part of the beam slightly below the horizontal centerline of the headlight, and slightly to the right of center (toward the edge of your lane). This setup lets you see far down the road while keeping the beam out of oncoming drivers' eyes. The beam should be sharper and brighter on the right side of the wall than on the left.

If the beam is too high, the bright spot will be well above the centerline, and oncoming drivers will complain about glare. If the beam is too low, the bright spot will be far below center, and you will have trouble seeing the road ahead. If the beam is off to one side, one headlight is aiming away from the center of the road.

Making the adjustment

Once you have identified which direction to turn the screws, make small adjustments — usually a quarter turn at a time. After each adjustment, step back and look at the beam pattern on the wall. It takes several small turns to get the aim right, so do not try to fix it all at once.

Adjust the vertical screw first to get the height correct, then adjust the horizontal screw to center the beam left to right. Work on one headlight at a time so you can see the change clearly. Once both headlights match the correct pattern, turn them off and turn on the high beams to make sure they are not also misaligned — high beams often share the same housing and may need adjustment too.

When to take your car to a shop

If your headlights are sealed units, if the adjustment screws are not accessible, or if you cannot get the beam pattern to look right after several attempts, a repair shop can aim them with a headlight aiming machine. This machine uses a level and a light sensor to measure the exact angle of the beam and tell the technician how much to adjust. The process usually takes 30 minutes to an hour and costs between $50 and $150 per pair, depending on the shop and the headlight type.

Some shops will aim your headlights while you wait. Call ahead to confirm they offer this service and ask whether they charge per headlight or per pair.

Frequently Asked Questions

Do I need special tools to adjust my headlights?

Most headlights use standard screwdrivers or small wrenches that you likely already have. Check your owner's manual to see what size tool fits your adjustment screws. You do not need a headlight aiming machine to do a basic adjustment at home — a wall and your eyes are enough to test the beam pattern.

Can I adjust my headlights during the day?

No. You need darkness to see the beam pattern clearly on the wall. Adjust your headlights at dusk or at night, or in a dark garage or enclosed space. Daylight will wash out the beam pattern and make it impossible to see whether the aim is correct.

What if one headlight is much brighter than the other?

Brightness difference usually means one bulb is older or failing, not that the aim is wrong. Replace both bulbs with the same type and age, then test the aim again. If one headlight still looks dimmer after you replace the bulbs, the lens may be cloudy or the reflector inside may be damaged — a shop can assess this.

How often should I check my headlight aim?

Check your aim once a year or after any collision or major pothole impact. If you notice oncoming drivers flashing their lights at you, check when ready — that is usually a sign your headlights are too high. Regular checks take only a few minutes and can prevent tickets and accidents.