Headlights aid in nighttime navigation on the road and help to improve visibility when you are driving in foul weather. A headlight bulb, like the bulb in a table lamp or flashlight, is a replaceable component of a headlight assembly.
Headlight bulbs come in one of four common types - halogen, LED, Xenon (otherwise known as HID lights), and Laser. Gone are the days when incandescent bulbs were used in automobiles, although they can still be found in older or classic cars.
Halogen headlight bulbs contain one or two filaments in a single bulb. Dual-filament bulbs allow for normal and bright light function in a single bulb. The filament is made of tungsten, and the glass bulb housing is pressurized with an inert halogen gas that allows the bulb to burn brighter and for a longer time. This is the most common type of headlight bulb in use today.
Xenon or HID (High-Intensity Discharge) lights are often used on higher-end luxury vehicles. They contain a combination of xenon and argon gasses mixed with vaporized metals and emit an extremely bright bluish light with a longer range of illumination than other types of light.
LED headlights allow for manufacturers to come up with more creative designs to fit tight spaces. They are also capable of producing extremely bright light. And they are energy efficient, even if they do tend to cost more.
The newest addition to the lineup is the laser headlight. They work through the process of chemiluminescence, producing light by triggering a chemical reaction. They are more efficient than even LED lights, but they produce more heat. They are also used only in high beam headlights to this point.
Regardless of the type of headlight used in your vehicle, the bulb can be removed and replaced when it becomes weak or burns out.
Headlight bulb replacement can be a relatively simple operation, and it can be quite complex. On some vehicles, a technician needs only to reach inside the engine compartment, remove a cover from the backside of the headlight assembly, detach a wire, unclip the bulb retainer, and remove the old bulb.
But more and more, access to the back of a headlight assembly is becoming more difficult. Other components might need to be removed for access. Some headlight bulbs are even accessed through the wheel well once the vehicle has been lifted and supported in the air and the tire and wheel removed. Still other vehicles require that the entire front bumper and grill assembly be removed for access, taking a significant amount of time and costing upwards of a thousand dollars to perform.
In every case, whether the repair is easy or difficult, the technician must use extreme care when handling a new headlight bulb. Simply allowing oil from the skin to contaminate the bulb can cause it to fail prematurely.