Headlights used to be simple because they were universal – you either had round or rectangular halogens and they all mounted in the same way. For many years, this was the norm with only exotic cars having expensive, tailored lights. In the 1980s and 1990s, though, this started to change and headlights began to be custom molded to the vehicle. By the late 1990s, the old halogens were out and new, more efficient, halogen bulbs were being encased in custom-designed headlamps.
These lamps give the automaker and designer a lot of leeway in terms of style, aerodynamics, and (of course) replacement income. This custom fitting also means that they aren’t always adjustable. So when your headlight is “off” and shining in the wrong direction, there is little you can do but replace the light or remove it and have the mountings adjusted (if that’s even possible).
Luckily, most auto manufacturers still have adjustments in their headlamp mounts so you can tune the light placement.
Adjusting the Beams
The procedure is roughly the same as it used to be with halogens, with only the location of the adjustment screws or the need for shims to be added being different.
Start by parking the vehicle on a level surface about five feet from a flat wall or plain surface. Take a roll of masking tape (or any tape that is easily visible and won’t leave marks on the wall you’re using) and put a little piece at the center of each headlight beam. Then run a straight line with the tape (or pencil along a straight edge) going from one center to the next. This creates your reference point.
Now back the vehicle to about 25 feet from the wall, still on a level surface, and park again. Your headlight beams, if properly adjusted, should be centered at exactly the same point, but two inches (give or take a quarter inch) above your reference points. The line between them should remain basically straight. If they are off to the left or right or up and down, you’ll need to make adjustments.
With the lights still on, do this by using the screws. If you must insert shims, then follow the proper procedure for headlamp mount screw removal, add the shims, and put them back in. Most modern cars still have adjustment screws you can access from behind the lights, inside the engine compartment.
You may need to follow this once each for low and high beams if they are separate bulbs or lamps.
Once the lights are properly adjusted, and if possible, leave your reference point for a day or two and drive your car. Then park it at your 25-foot point and measure again. If things are off, you likely have a broken mount that is wiggling and causing adjustment to change. You’ll need to repair or replace.