Aligning a car's headlights involves parking close to a wall, marking the center of each headlight, and then backing the car 30 feet away before adjusting screws to center the lights on the mark, according to CarsDirect. If the headlights seem dim for night driving, the problem is sometimes alignment.
Some vehicles make the process of aligning headlights easier by adding bubble levels on the lights, according to Popular Mechanics. However, some vehicles may not provide adjustment screws for the horizontal aim. Problems with horizontal alignment are less common, but if they occur, shims are required to adjust the lights.
To ensure accuracy in adjusting headlights, the owner should check the tire pressure, and add air as necessary to ensure proper inflation before turning any screws, according to Popular Mechanics. He should only make the adjustment when the fuel tank is half full and someone is sitting in the driver's seat. Before making adjustments, it is essential to bounce each side of the car to stabilize its suspension.
On vehicles with separate lamps for the high and low beams, it is necessary to check and adjust the lamps individually, reports Popular Mechanics. Some auto manufacturers place the adjustment screws behind other equipment in the engine compartment. To make adjustments, the owner must remove this equipment and reinstall it after finishing the job.