Different types of car bulbs, how they work, and how to replace them with new ones

Sarah Parker
Authored by Sarah Parker
Posted: Sunday, September 26, 2021 - 21:52

Lighting on a vehicle has three purposes: to make you visible, to aid in seeing, and to give you a signal. It's common to find different types of bulbs in a headlight, each one serving a different function.

Bulb Types: 


The main/dip bulbs of all headlights were filament lights until relatively recently. Similar to normal household bulbs, they work by heating up a thin metal filament by means of an electrical current. 

Generally, the bulbs are filled with halogen gas, which allows the bulbs to operate at a hotter temperature and therefore emit more light. 

Bulb bulbs can sometimes be filled with xenon gas to give them brighter, whiter lighting. 

Additionally, indicators and sidelights use this technology, although they are steadily being replaced by LEDs. 

The image of the types of bulbs taken from www.buycarparts.co.uk


HIDLights are defined as high-intensity discharge lights, and they don't have a filament like regular bulbs. Xenon gas is forced to leap across electrodes in a glass tube filled with electrodes to create light. They operate on a gas discharge principle. 

The ballast, which is a box of electronics that turns on the light as well as controls its output, is required for them. Compared to normal filament bulbs, they are brighter and whiter and usually last longer about 2000 hours 


Light Emitting Diodes are increasingly used for headlights due to their low power consumption and long life. New cars only have these lights for the main and dip beams, but they're increasingly used for indicators and sidelights. 

LEDs are an alternative to filament bulbs, but the car may think they are defective because of their low power consumption, triggering warning lights on the dashboard. 

In this case, a 'CANbus LED' is needed, which has a tiny resistor built in to simulate the power consumption of a conventional light bulb. You should also check the national regulations. When a vehicle does not come with a standard LED bulb built into one of the light units, the vehicle will fail the annual MOT inspection.

Changing a Headlight Bulb is easy in 4 steps

First, find the best replacement bulb and tools to use. If your vehicle is compatible with a certain type of bulb, your local auto parts retailer can help you find the bulb's compatibility will be determined by the vehicle's make and model. 

  • Locate the headlight holder
  • Remove the power wires
  • Clean and install the new bulb