The headlights must be aimed correctly to avoid blinding oncoming drivers and to ensure optimal visibility on the road. It is important to check the aim every 12 months or whenever a new headlight is installed or front-end body work is done. The adjustment procedure provides only a temporary fix until a professional can make the necessary adjustments. Each headlight has two adjusting screws, accessible from the rear of the assembly, with Navigator models requiring only horizontal adjustments and later Expedition/Navigator models having a single vertical adjuster. To adjust the headlights, use masking tape on a blank wall to mark the vehicle centerline and headlight centerlines, positioning a horizontal tape line for reference. The vehicle should be parked 25 feet from the wall, level, with a half-full gas tank and no heavy load. For low beam adjustment, the high-intensity zone should be set two inches below the horizontal line and two inches to the right of the vertical line, using the top screw to raise or lower the beam and the side screw to move it left or right. With high beams on, the high-intensity zone should be centered just below the horizontal line. If a compromise is necessary, prioritize low beam adjustments for safety, and have the headlights properly adjusted by a dealer or service station as soon as possible.