Over time, headlights can loosen in their assembly and shift the aim of the lamps. But sometimes it is because the suspension of the vehicle is sagging or simply because you’re carrying too heavy of a load in back and it is tilting the front of the vehicle upwards.
It is important to make sure that it is the headlight and not the suspension or load causing the problem, before you decide to adjust the lamps. In some vehicles, like Acuras and Hondas, there are bubble levels in the headlamp assembly expressly for the purpose of checking the headlight position.
Otherwise, place the vehicle on a very flat surface, using a carpenter’s level to check the evenness of the ground surface. Make sure that the tires are inflated properly and push the suspension on each side of the front end a few times, to settle the suspension. Have a driver in the front seat for proper checking.
Then, look at the bubble levels in the assembly, or use a measuring stick and carpenter’s level to check yourself. To examine further, take the vehicle to where you can aim the headlights at a wall 25 feet in front of the vehicle and ensure the aim is straight ahead.
If you determine that the aim is off, use your vehicle’s manual to locate the headlight adjusters. Once you get to them, use the wall at night to aim the headlights and check your progress as you adjust the lamps. Once you see the strongest part of the beam is aimed at the center of each of the beams, directly across from the vehicle, you can be sure your headlights are adjusted correctly.