Adjusting your car's headlights is a straightforward DIY task that ensures safe nighttime driving. The core process involves parking on a level surface facing a wall, marking the current headlight beam centers on the wall, and then using adjustment screws on the headlight housing to align the beams to the correct height and horizontal aim. Properly aimed headlights maximize your visibility without blinding other drivers.
Before you start, you'll need a few basic items: a Phillips screwdriver, a tape measure, masking tape, and a level surface like a garage or empty parking lot facing a wall. It's best to do this at dusk or night for clear visibility of the beams.
Step 1: Preparation. Park the car on a level surface about 3 to 5 feet from a wall. Check that the tire pressure is correct and that there isn't any heavy load in the trunk. Bounce the car on its suspension a few times to settle it. Turn on your low-beam headlights.
Step 2: Mark the Wall. Place a long strip of horizontal masking tape on the wall, running directly in front of the center of each headlight. Mark the vertical centerline of the car on the tape. Then, mark the exact center point of each headlight's hot spot on the tape. This is your reference point.
Step 3: Locate the Adjustment Screws. Pop the hood and locate the adjustment screws on each headlight assembly. There are typically two screws: one controls the vertical aim (up and down) and the other controls the horizontal aim (left and right). They may be labeled or require a Phillips screwdriver.
Step 4: Make the Adjustments. Back the car away from the wall exactly 25 feet. The light beams should now be lower than your reference marks. For most vehicles, the top of the most intense part of the low-beam pattern should be 2 inches below the horizontal tape line you made. Use the adjustment screws to center the beams on this new, lower target. Turn the screws slowly, checking the pattern on the wall after each small adjustment.
| Vehicle Type | Recommended Drop at 25 Feet | Horizontal Aim |
|---|
| Sedan / Coupe | 2 inches | Straight ahead or slightly outward |
| SUV / Truck | 2 to 4 inches (higher vehicles need more drop) | Straight ahead |
| With Heavy Load | 3 to 5 inches (to compensate for rear sag) | Straight ahead |
| Projector Headlights | Follow the sharp cut-off line | Align the "step" pattern |
After adjusting the low beams, test your high beams briefly; they should be centered and significantly brighter. Always do a real-world test drive on a dark road to confirm the aim feels correct. If the headlights are still misaligned or you're uncomfortable, a professional mechanic can perform a precise alignment with an optical aimer for a small fee.
