What is Headlights Aiming, headlight adjustment or Alignment?


The headlights must be aimed correctly to the required direction to get proper light on the road and to prevent the vehicle from an accident. If the headlights are aimed too high or to low they might blind an oncoming driver, causing the accident. Incorrect aiming of the headlight will not illuminate the road properly. For correct headlight aiming, most American cars have four headlamps, two headlamps are arranged in each side. (Fig. 26.2). The two headlamps can be arranged in a horizontal row or in a vertical row on each side. The headlamp may be either of one filament type or two-filament type. The two-filament type is always placed outside or above the one filament lamp.

Headlights Aiming, headlight adjustment or Alignment.

The headlights have three aiming buttons on the front lens. The adjustments are made by turning spring-loaded
 screws. There is one spring loaded screw at the top for up and down adjustment and one at the side for the left to right adjustment.


The headlamps must be properly aimed to obtain the maximum results in road lumination. There are several methods of checking the headlights aiming. The simplest method is as follows:

Headlights Aiming, headlight adjustment or Alignment.
Headlights Aiming, headlight adjustment

Place a vertical screen 7.5 m in front of the vehicle. The vehicle must be aligned perpendicular to the screen. The floor should also be in level. Draw a horizontal line on the level surface 7.5 cm below the headlamp center. See through the center of the rear window over the center of the radiator ornament and so determine a point on a horizontal line midway between the headlamps.

Headlights Aiming, headlight adjustment or Alignment.

Headlight Alignment

Draw tical lines through the point at the right and left of this center point directly ahead of the center of each headlamp. Place the lighting switch on to produce an upper beam (bright light). The lower filaments on both lamps are also illuminated when the upper beam is lighted.

The light beam may be moved to the right or left by the horizontal adjusting screw. The light beam may be raised or lowered by the vertical adjusting screw. Cover one lamp to observe the light beam and then adjust the beam from the other lamp so that the center of the zone of highest intensity (hot spot) falls on the intersection of the horizontal line 7.5 cm below the headlamp center and the vertical line directly ahead of the lamp. Repeat the operation for the other lamp. No further adjustment is required for the lower beam.

Watch the video below to know how headlights aiming adjustment is done?

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