What are the different types of headlight bulbs?
Updated 11 Oct 2019
Having a working set of headlights is, of course, a fundamental safety requirement.
Take a trip at night without them and not only won’t you be able to see where you’re going, but other road users are going to have a hell of a time seeing you. It’s a recipe for disaster.
So, working headlights – on both the passenger and driver’s side of the car – are a must.
Back in the day, car headlight bulbs were all filament bulbs, working in the same way as household bulbs – electricity passes through a filament that heats up and emits light.
Today, lighting technology has moved on and there are three main types of bulb used in vehicles.
- HID (High Intensity Discharge)
- LEDs (Light Emitting Diode)
WHAT IS THE DIFFERENCE BETWEEN THE THREE TYPES OF BULBS?
Starting with the oldest design, the halogen bulb is one of the most commonly used bulbs in the automotive industry, mainly due to being easy and cheap to manufacture and easy to replace.
Halogen bulbs operate by a tungsten filament, which when current flows through it, creates heat and light.
These bulbs are filled with a halogen gas, hence the name, which prevents the bulb from turning black.
This is why, when the globe fails, there may be a black mark on the side of the glass.
The downside to these bulbs is that they are not as bright as other options, and also consume more electricity, putting more stress on the electrical system of the vehicle.
These bulbs are slowly being phased out on newer vehicles, as manufacturers move into more advanced technology, for safety and efficiency purposes.
HID (High Intensity Discharge):
First seen on many high end and luxury cars, the HID headlight bulb has become more common on lower specification models as the technology has become more readily available.
The easiest way to tell if a vehicle is fitted with HID bulbs is the distinct white/blue tinge that the light gives off.
HID headlights are much brighter than their halogen counterparts, increasing visibility.
These bulbs are filled with xenon gas, which is ignited via an electric arc between two electrons inside the bulb.
Xenon gas takes an enormous amount of voltage to ignite, which is controlled via a ballast fitted inside the headlight housing.
These bulbs are more expensive to replace, and can cause injury if not handled with care.
LED (Light Emitting Diode):
The latest innovation in headlight bulb technology is the LED bulb.
These bulbs are made up of a number of light emitting diodes, which light up when voltage is passed through them.
They provide a large amount of light without using much energy, and have very long lifespans.
They are also shock and vibration resistant, which makes them perfect for automotive applications.
TIPS TO REMEMBER
When one headlight burns out, particularly in the case of filament bulbs, both the driver and passenger side headlight bulbs should be replaced.
When one goes, the other will probably not be far behind.
Headlight lenses can become cloudy and scratched through general wear and tear.
This will have a negative effect on the light emitted from the bulb.
A bulb replacement is a good time to get the wiring, fuses and connections professionally checked.
These should be maintained so that more, and more frequent, headlight issues can be avoided.
HOW IMPORTANT IS MAINTAINING THE HEADLIGHT
There could hardly be a clearer safety issue than a headlight failure.
Legally, you can’t drive at night without them and if you do - or if you only have only one working headlight - then you put everyone on the road around you, including yourself, at risk.
There’s also the potential, should you be involved in an accident in these circumstances, of any insurance claim being refused. No one wants that.
If you’re headlights are no longer working and you suspect it may be the bulbs, you can easily book in with a quality mechanic on AutoGuru to get them replaced.
They’ll be able to recommend which type of bulb is best for your car and fit them up in no time!
Jonathan has been writing about the auto industry for years and is particularly interested in the high-tech innovations sweeping the industry.
He’d love to own a Tesla Model S, but also adores anything with a V8 under the bonnet.
He has yet to decide between an EV or a Mustang for his next ride.