What is the lighting/what does it do?

The vehicle lighting system is a complex series of lights and signalling components that are attached to the front, rear and sides of a vehicle as well as the interior of the vehicle for the use of the driver and passengers.

Getting into the details of the lighting

The lighting is most commonly provided by anti-glare halogen bulbs that are encased in a plastic cover to allow the light to reflect out. There has also been a recent influx of xenon lighting. These HID (High Intensity Discharge) bulbs are high voltage and can provide up to 300% more light compared with a halogen bulb. They don’t have a filament like ordinary bulbs, instead they use xenon gas which is ignited by ballast at an intensity of 20,000 volts. These bulbs have a much longer shelf life than ordinary halogen lights.

Each type of the vehicle’s external lighting has its own function. The headlights, for example sit on the front of the vehicle above the bumper and are enclosed in their own housing. They are powered by the vehicle’s battery and connected to the power supply. They are controlled by a switch on the headlight stalk in the vehicles’ interior, and are operated by the driver of the vehicle. When the headlight switch is used, an electrical signal is relayed from the battery to the headlights and turns them on.

Vehicles also have indicator lights situated on the rear of the vehicle so other road users know which way the vehicle is turning. These lights sometimes work in conjunction with side indictor lights, which as the name suggests are located on the side of the vehicle. In combination, these lights enable road users from any direction to see if the vehicle is indicating. As with the headlights these lights are controlled by the vehicles’ power supply.

Brake lights are also an essential part of your vehicle, and are located on the rear of the vehicle. Their job is simple, to alert drivers behind you to your braking so that they can brake in time to avoid hitting your vehicle.

Vehicles also have fog lights (sometimes known as spotlights). These lights are used in times of extremely poor visibility, for example in fog or during heavy snow. These lights are much brighter than general headlights and can dazzle oncoming drivers, hence why they are only used in times when it’s very difficult to see.

What if something goes wrong with the lighting?

All of these lights are essential, and some of them (the headlights for example) are an MOT failure if they are not operating correctly. It’s therefore important that they are maintained regularly.

Should any of these lights fail, your first step should be to check the bulb to see if it’s expired. If this doesn’t correct the issue you should check the fuse and replace if necessary. If the light is still not working this could be an electrical fault. As with all vehicle electrics, if you are not confident in working with electrics it’s recommended that you take the vehicle to a reputable repair centre.

Lastly, we should discuss the interior lights of the vehicle. These are less important lights than the ones on the outside of the vehicle and generally don’t affect the safety of the vehicle. They are however, useful lights, particularly the ones on the dashboard. These lights illuminate the dials so the driver can see their speed, their mileage and other vehicle functions.

The other interior lights are situated in the roof and foot well of the vehicle and illuminate the vehicles’ interior so the driver and passenger can see inside the vehicle in the dark.