Symptoms
- One headlight beam pattern looks different from the other
- Oncoming drivers flash their lights at you frequently
- Road ahead seems poorly lit even with headlights on
- Beam pattern looks tilted to one side
Likely causes
- CommonAdjuster knocked out of positionHitting a curb, pothole, or having front-end work done can shift the headlight aim.
- CommonIncorrect bulb type or wattage installedA bulb that doesn't match the housing's design can create an uneven or misdirected beam.
- PossibleSagging suspension or uneven vehicle loadA vehicle sitting unevenly (heavy trunk load, worn springs) can throw off headlight aim relative to the road.
- PossibleLoose headlight housing mountingA housing that's not securely mounted can shift position over time or after an impact.
What to do
- Park on level ground facing a wall or garage door about 25 feet away to check the beam pattern.
- Compare both headlights' beam height and position on the wall; they should be level and symmetrical.
- Check the owner's manual for the location of headlight adjustment screws, usually accessible from the engine bay.
- Use the adjustment screws to raise, lower, or shift the beam left/right as needed, making small adjustments and rechecking.
- Remove any unusually heavy loads from the trunk that could be tilting the vehicle and affecting aim.
- Check that the headlight housing itself is securely mounted with no visible looseness.
- Recheck aim after any front-end repair work or after replacing a headlight bulb or housing.
- Have a shop perform a proper headlight aim adjustment with specialized equipment if DIY adjustment isn't accurate enough.
Tools and parts
- Screwdriver (for adjuster screws)
- Flat wall or garage door for aiming reference
- Tape measure
When to call a pro
A shop with proper headlight aiming equipment can achieve a more precise adjustment than eyeballing it against a wall.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.