Headlight Adjustment

headlightsIt is important to have your vehicle’s headlights aimed properly. Too low and they won’t light the road well, too high or too far to the left, and your lights will blind oncoming traffic.

When replacing bulbs, it is a good idea to verify that your lights are also properly aimed. Slight variances in filament position can translate to large variances in beam pattern.

Step 1:

Find a flat and level surface adjacent to a vertical wall (preferably white) where the car can be parked. Pull the car straight up to the wall as close as possible and mark a vertical line corresponding to the centerline of the vehicle. (Blue painter’s tape works well, but any masking tape will do.) This can be done most precisely by using a yardstick and extending it from the hood ornament or badge – to the wall). Pull the car straight back until the headlights are 25 feet from the wall.

Make the following two measurements:
Measurement A: From the ground to the center of one of the headlight lenses.

Measurement B: From one of the low beam headlights to the vehicle centerline.

Measurement C: From high beam center to vehicle centerline (for 4 headlight systems).

Note these measurements.


(A) Two Headlamp Systems:
Tape one horizontal line on the wall at a height exactly 2 inches lower than Measurement A.

On the line, make vertical marks both to the right and left of the vehicle centerline mark
at the distance of Measurement B from the vehicle centerline – vertical tape line.


(B) Four Headlamp Systems:
Draw two horizontal lines on the wall, one at the height measured from the ground to center of the
headlight and one at a height exactly 2 inches lower than the measurement from the ground to
the center of the headlight.

Make vertical marks for the low beam on the lower line and vertical marks on the upper line for the high beam as in Part (A) above (the
high beam marks are made at a distance corresponding to the high beam measurement made in Step 2).


(A) Two Headlamp Systems:
Turn the headlights on and adjust the vertical aim of the headlights so that the top horizontal
cutoff of each of the beams is located along the horizontal line drawn on the wall. Adjust the
horizontal aim of the low beam headlights so that the point at which the top cutoff of the beam
begins to slope upwards is located at the vertical marks made in Step 3 (A).

(B) Four Headlamp Systems:
Adjust the low beams as in (A) above.
Adjust the high beams so that the center of the illuminated
region is located at the cross formed by the upper horizontal line and the vertical marks made in
Step 3 (B) above.

Enjoy your better vision!