You can adjust most headlights yourself in 15 minutes with basic tools
Headlight adjustment is a job you can do in your driveway without special equipment. Most vehicles have adjustment screws or bolts behind the headlight assembly — usually accessible from inside the engine bay — that let you move the beam up, down, and side to side. The process takes about 15 minutes per headlight and requires only a Phillips or flathead screwdriver, depending on your vehicle.
The reason to adjust is straightforward: if your headlights point too high, you blind oncoming drivers; if they point too low, you cannot see the road ahead. Proper aim also means your low beams reach farther down the road, which matters more than brightness for safe night driving. Most states have inspection standards for headlight aim, and some shops will check it for free or charge $20 to $50 if you want a professional to verify the job.
Key Takeaways
- Headlight adjustment screws are located behind the headlight assembly in the engine bay, usually marked with up-and-down and left-right symbols.
- You need a level surface, a wall or garage door at least 25 feet away, and a screwdriver that fits your vehicle's adjustment screws.
- The beam should hit the wall at or slightly below the height of your headlights, with the brightest spot aimed straight ahead or slightly downward.
- If you cannot locate the adjustment screws or your headlights are sealed units, a shop can adjust them for $20 to $50 or check your work for free.
Locate the adjustment screws behind your headlight assembly
Open your hood and look directly behind the headlight you want to adjust. You will see the back of the headlight housing — a plastic or metal assembly with wires connected to it. On that back surface, you should see two screws or bolts, usually with small symbols next to them: one marked with up-and-down arrows (for vertical aim) and one marked with left-right arrows (for horizontal aim).
The location varies by make and model. On some vehicles, the screws are on top of the headlight assembly; on others, they are on the sides or bottom. Your owner's manual will show the exact location and which tool fits — most use a Phillips screwdriver, but some use a flathead or a 10mm socket. If you cannot find the screws after checking the manual, your headlights may be sealed units that cannot be adjusted at home, and you will need a shop to do it.
Set up a test wall and measure the beam height
Park your vehicle on a level surface facing a blank wall, garage door, or large white surface at least 25 feet away. The distance matters: at 25 feet, small adjustments to the screw create visible changes in beam position. Turn on your low beams and turn off all other lights so you can see the beam pattern clearly.
Mark the center of the beam on the wall with tape or chalk — this is your reference point. The beam should hit the wall at approximately the same height as your headlights, or slightly below. If the beam is hitting well above that point, your headlights are aiming too high and need downward adjustment. If it is hitting well below, they need upward adjustment. Take a photo of the beam position before you start turning screws, so you have a record of where you began.
Turn the vertical adjustment screw to aim up or down
Start with the vertical adjustment screw — the one marked with up-and-down arrows. Turn it clockwise to aim the beam downward, and counterclockwise to aim it upward. Make small quarter-turn adjustments and check the wall after each one. The goal is to move the brightest part of the beam so it hits the wall at the height of your headlights or slightly below.
Most vehicles aim the low beam so the top edge of the bright spot is at or just below the headlight height. This gives you maximum distance on the road without blinding oncoming traffic. If you are unsure of the exact aim, aim slightly low — it is safer than aiming high. Once the vertical aim looks right, move to the horizontal adjustment.
Turn the horizontal adjustment screw to aim left or right
The horizontal screw — marked with left-right arrows — controls whether the beam points straight ahead or angles inward or outward. Turn it to move the brightest spot left or right on the wall. The goal is to center the beam so it points straight ahead, or slightly inward toward the center of the road.
Some vehicles aim the low beam slightly inward (about 2 to 3 inches to the right of center at 25 feet) to light the right side of the road better without blinding oncoming drivers in the left lane. Check your owner's manual for the manufacturer's recommended aim, or aim straight ahead if the manual does not specify. Make quarter-turn adjustments and check the wall after each one, just as you did with the vertical screw.
Repeat the process for the second headlight
Once the first headlight is adjusted, repeat the same steps for the other side. Park in the same spot, mark the beam on the wall, and adjust both the vertical and horizontal screws until the beam matches the aim of the first headlight. Both beams should hit the wall at the same height and in the same horizontal position — if one is higher or lower than the other, the difference will be obvious and distracting while you drive.
After adjusting both headlights, turn them off and turn on your high beams to check that they work and aim higher than the low beams, as they should. If your high beams are also misaligned, they usually share the same adjustment screws as the low beams, so the adjustment you just made affects both. Some vehicles have separate high-beam adjustment, but most do not.
When to take your headlights to a shop instead
If you cannot find the adjustment screws after checking your owner's manual, or if your headlights are sealed units with no visible screws, a shop can adjust them using a headlight aiming machine. These machines use a level and a light sensor to measure beam angle precisely, and they cost shops $500 to $2,000 to buy. Most shops charge $20 to $50 per vehicle to use one, or they may check your work for free if you adjusted them yourself.
You should also take your headlights to a shop if you have HID (high-intensity discharge) or LED headlights, which are more sensitive to aim and may require special tools or calibration. If you adjusted the screws and the beam still does not look right, or if the adjustment screw is stuck or stripped, a shop can diagnose the problem and replace the adjustment mechanism if needed.
Frequently Asked Questions
How often do headlights need adjustment?
Headlights rarely drift out of aim on their own unless you hit a pothole hard enough to damage the headlight housing or suspension. If your aim was correct and has shifted, check whether the housing is cracked or loose. Otherwise, you may only need to adjust them once every few years, or after any collision that affects the front end.
Can I adjust headlights at night?
Yes, and night is actually better because you can see the beam pattern more clearly. Use the same 25-foot distance and a blank wall or garage door. The only downside is that you need a helper to turn the headlights on and off while you adjust the screws, or you need to run back and forth to the driver's seat.
What if one headlight is much brighter than the other?
Brightness difference usually means one bulb is older or failing, not an aim problem. Both low beams should be the same brightness. If one is noticeably dimmer, replace that bulb first, then check the aim. If both are equally bright but one seems to light the road less, the aim is probably off.
Do I need to adjust headlights after replacing a bulb?
No. Replacing a bulb does not change the aim of the headlight. The adjustment screws control the position of the entire headlight assembly, not the bulb itself. If you replaced a bulb and the aim now looks wrong, the old bulb may have been sitting in a different position due to wear, and the new bulb is now showing you the true aim.
What if my headlights have adjustment screws but they will not turn?
The screw may be stuck due to corrosion or overtightening. Try spraying penetrating oil (like WD-40) around the screw and waiting 15 minutes, then try again with steady pressure. Do not force it — if it still will not budge, take it to a shop rather than risk stripping the screw or cracking the housing.