If you have ever been blinded by oncoming traffic or in your rearview mirrors by badly aimed headlights, you know how important proper headlight aim is. Projector headlights have more intense beams, and those beams have a sharper cut-off from illumination to darkness. Aiming them is simple, but may require a specialised tool to actuate the adjusters.
Choose a location with a garage door or wall facing a level surface, like a level driveway or car park. Even a slight incline can ruin the measurements you will need to take in order to aim your projector-beam headlights effectively.
Make sure that your car is in its normal configuration; in other words, if you have heavy items in the boot that aren't normally there, remove them. This will ensure accuracy of aim.
Use the measuring tape to measure the exact distance from the centre of the headlight itself to the ground. Now use it to measure the distance from headlight to headlight.
Using the measurements you just took, mark the height of each headlight on a garage door or wall with masking tape. Check your measurements to make sure they are exact. Then, mark the horizontal position of each headlight, using the width measurement you took. You should now have two "+'s" on the wall, marking the horizontal and vertical reference points for your car's headlights. Now mark two more spots that are 2 inches below the two "+'s."
Move your vehicle back so that its headlights are exactly 25 feet from the wall. It should be aiming directly between your two marks. Confirm this by "sighting" through the rear glass and windshield, from the rear of the car. Open the bonnet of your car and locate the rear of each headlight assembly. Consult your owner's manual if you have trouble finding the adjustment points. Your vehicle may require a specific speciality driver to adjust this assembly, such as a star-shaped driver, so check which one and what size it needs before proceeding.
Turn on the low beams. Cover one headlight with a towel and adjust one headlight at a time. Adjust the screws at the rear of the headlight assembly so that the centre of the beam aims exactly at the centre of the "+" horizontally, and at the 2.1-inch lower mark vertically. This will give you the 0.4-degree beam drop that is the U.S. standard, regardless of the height of the vehicle.
Repeat the procedure for the other headlight.