You can adjust most headlights yourself in 15 minutes with basic tools
Headlight adjustment is one of the few repairs you can do without a mechanic. Most vehicles have adjustment screws or bolts behind the headlight housing — usually two per light, one for vertical aim and one for horizontal. You'll need a screwdriver (Phillips or flathead, depending on your car), a wall or garage door, and about 15 minutes. The goal is to point the beam so it lights the road ahead without blinding oncoming drivers.
Misaligned headlights are a safety problem that gets worse the longer you ignore it. A light pointing too high washes out your vision of the road and blinds other drivers, causing them to brake or swerve. A light pointing too low means you can't see potholes, debris, or pedestrians until you're nearly on top of them. If you've hit a pothole, curb, or another car, or if one headlight suddenly looks dimmer or angled wrong, adjustment is the first thing to check before assuming the bulb is failing.
Key Takeaways
- Most headlights adjust with two screws per light — one moves the beam up and down, the other moves it left and right.
- You can test alignment yourself by parking 25 feet from a wall, turning on the low beams, and checking where the light pattern hits.
- The beam should point slightly downward and toward the center of the road, not straight ahead or upward.
- If you cannot locate the adjustment screws or the light won't move when you turn them, the housing may be damaged and need replacement.
- Some newer vehicles have electronic headlight leveling systems that adjust automatically; check your owner's manual before attempting manual adjustment.
Locate the adjustment screws behind the headlight housing
Open your hood and look directly behind the headlight that needs adjustment. You'll see the back of the plastic or metal housing. On most cars, there are two screws or bolts sticking out from the housing — one on top or the side (vertical adjustment) and one to the side (horizontal adjustment). They may be Phillips head, flathead, or hex bolts depending on the make and model.
If you cannot find them, check your owner's manual for the exact location — some vehicles hide them under a rubber cap or behind a removable panel. On a few older models, the adjustment mechanism is inside the engine bay but accessed from underneath the car. If the housing looks cracked, melted, or loose, stop here. A damaged housing won't hold adjustment and needs to be replaced as a unit.
Park on a level surface and test the current beam pattern
Drive to a flat, empty wall or garage door at least 25 feet away. Park straight and level, with the car about 2 feet from the wall. Turn on the low beams (not high beams) in darkness or dim light so you can see the pattern clearly. Mark the center of each light beam on the wall with tape or a marker.
The correct pattern for low beams is a sharp cutoff line that sits slightly below the horizontal center of the wall, with the beam angled slightly to the right (toward the shoulder of the road). If both beams are pointing too high, too low, or too far to one side, you have adjustment work to do. Take a photo of the current pattern so you can compare it after adjustment.
Turn the vertical adjustment screw to aim the beam up or down
The vertical screw is usually on top of the housing or on the inner side closest to the engine. Turn it slowly — usually clockwise raises the beam and counterclockwise lowers it, but check your manual to be sure. Make a quarter-turn, then walk back to the wall and check the pattern. The beam should move noticeably.
Adjust until the top edge of the beam (the sharp cutoff line) sits just below the horizontal center of the wall. This position prevents glare in oncoming drivers' eyes while keeping the road visible to you. If the screw spins freely without moving the beam, the adjustment mechanism inside the housing may be broken, and the housing will need replacement.
Turn the horizontal adjustment screw to aim the beam left or right
The horizontal screw is usually on the outer side of the housing, facing away from the engine. Turn it slowly — usually clockwise moves the beam toward the center of the car and counterclockwise moves it outward. Make a quarter-turn, check the wall, and repeat until the beam points slightly to the right of center (or toward the shoulder on the side of the road where that light sits).
The goal is symmetry: both beams should form a similar pattern on the wall, with the cutoff line at the same height and the beams angled the same direction. If one light is much brighter or dimmer than the other after adjustment, the bulb may be failing or the reflector inside the housing may be damaged. Brightness difference is not fixed by aiming — it requires bulb replacement or housing replacement.
Check your work on the road and fine-tune if needed
Drive on a dark, empty road and watch how the beams light the pavement ahead. You should see the road surface clearly 100 to 150 feet ahead without glare washing out detail. Oncoming traffic should not flash their lights at you, which is a sign you're blinding them. If the beams still feel wrong, return to the wall and make smaller adjustments — quarter-turns are often too large once you're close to correct.
Some vehicles have separate low and high beam adjustment, though most cars adjust both together. If your high beams are misaligned but your low beams are correct, the high beam reflector inside the housing may be damaged. High beam reflector damage usually requires housing replacement, not adjustment.
When to stop adjusting and replace the housing instead
If the adjustment screws turn but the beam doesn't move, the internal mechanism is broken. If the housing is cracked, melted, or visibly loose, adjustment won't hold. If one light is much dimmer than the other even after you've confirmed the bulb is good, the reflector coating inside is damaged. In all these cases, the housing unit needs replacement, not adjustment.
Replacement housings range from $150 to $400 per side depending on whether they're OEM (original equipment) or aftermarket, and whether they include the bulb. Some newer vehicles with LED or HID headlights cost significantly more. A mechanic can replace one in 30 minutes to an hour. If you're not confident in your adjustment work, a shop can do a professional alignment for $50 to $100 per light, which is worth the cost if you're unsure.
Frequently Asked Questions
Can I adjust my headlights if I have LED or HID headlights?
Yes, the adjustment mechanism is the same. However, some newer vehicles with adaptive LED systems adjust automatically based on steering angle and speed. Check your owner's manual — if your car has automatic leveling, manual adjustment may override it or cause problems. Call your dealer before attempting adjustment on a vehicle with adaptive headlights.
What if I adjust one light and it still looks dimmer than the other?
Dimness is a bulb or reflector problem, not an aim problem. Check that both bulbs are the same type and wattage, and that neither is burned out. If the bulbs match and one light is still dim, the reflector coating inside that housing is damaged and the housing needs replacement.
How often do headlights need adjustment?
Properly adjusted headlights should stay aligned unless you hit something hard enough to damage the housing or frame. If you've been in a collision, hit a large pothole, or notice the beam suddenly pointing wrong, check alignment. Normal driving does not knock headlights out of aim.
Do I need a special tool to adjust headlights?
No. A Phillips or flathead screwdriver is all most cars need. Some vehicles use hex bolts, which require a wrench or socket set. Your owner's manual will tell you which tool fits your model. Avoid using power tools — you can easily strip the screws or break the housing.
What's the difference between low beam and high beam adjustment?
Low beams have a sharp cutoff line designed to light the road without blinding oncoming traffic. High beams point straight ahead and upward to light a wider area. Most cars adjust both together with the same screws. If only your high beams are misaligned, the high beam reflector inside the housing is likely damaged.