Auto Headlight Assembly

Headlights—or headlamps, as they are commonly referred to—are a type of auto part that doesn’t seem to need much explanation when you initially think about them. They simply attach to the front of your car or truck and light up the darkness so that you can see and drive safely at night. Easy enough, right?

Well, yes and no. When electric auto headlights first arrived on the automotive scene, they took the place of kerosene burning lanterns—which were not only fire hazards but were also not very bright and often blew out. Needless to say, electric headlights received a warm welcoming. With the magic of electricity and two little wires, they turned on, stayed lit on windy days, and gave drivers much better nighttime vision.

By 1940, “Sealed Beam” headlamps with glass lenses became a requirement on all vehicles in the United States. This was great, largely because the four different styles were amazingly cheap and plentiful. On the downside, automotive headlights became a car designer’s worst nightmare because of their one-size-fits-all shape. Luckily, that rule only lasted 43 YEARS! Yikes!

When 1983 arrived, it was a beautiful time to be a car headlight. The sealed beam headlight was no longer required, and plastic lenses were now allowed. This is the moment in time when the auto headlamp started to become complicated. First, composite halogen headlights arrived, which finally had replaceable halogen bulbs. This made headlight repair incredibly easy. Composite headlights were also designed to improve the look of the car. This often called for an integration of corner lamps and parking lights with the front headlights.

The 1990s brought the next significant change with fancy new "High Intensity Discharge" (HID) and xenon headlight technology. An HID headlight bulb is filled with xenon gas, which—with the help of an HID headlight ballast—increases the bulb's brightness and life span. Unfortunately, they come at a higher price point than the boring old sealed beam and composite halogen headlights.

That brings us to projector headlights. Projector headlights may use halogen or xenon bulbs, and they direct the light perfectly out the front of the car with the help of a small, movable metal shield. This shield is controlled by an electric motor and automatically moves when the high beam switch is activated. As you can imagine, moving parts inside a headlight assembly can lead to more problems, even when in the most delicate of accidents.