Fog Light change & replacement made easy

How does a fog light work?

Fog lights are designed to improve visibility in poor weather conditions such as thick fog, heavy rain, or snow. In the UK, all cars must have at least one working rear fog light to make your vehicle visible to drivers behind when visibility drops below 100 metres.

Many cars also feature front fog lights, which sit lower on the front bumper and shine a wide, low beam that lights up the road surface directly in front of your vehicle. This helps reduce glare and prevents light from reflecting back off the fog.

Unlike regular headlights, fog lights use a brighter, more focused beam aimed downwards. They’re usually operated manually via a dedicated button or switch on the indicator stalk, and a dashboard warning light shows when they’re on.

Rear fog lights are often built into the rear light cluster, while front fog lights are usually separate units. Remember to switch them off when visibility improves, leaving fog lights on unnecessarily can dazzle other drivers and may result in a fine.

When should I turn on my fog lights?

In the UK, fog lights should only be used when visibility is severely reduced, typically when you cannot see more than 100 meters ahead, roughly the length of a football pitch. This usually happens in thick fog, heavy rain, or snow.

Fog lights are designed to make your car more visible to other drivers, not to help you see the road better. In normal conditions, their bright light can dazzle other drivers, so using them when visibility is clear can be dangerous and may result in a fine.

Always switch off your fog lights when visibility improves to avoid obscuring your brake lights and to keep the road safe for everyone. Keep an eye on weather conditions, and when in doubt, only turn on your fog lights when visibility is truly poor.

Is it illegal to drive with fog lights on in the UK?

Yes, it can be illegal to drive with your fog lights on in the UK if visibility is clear.
Fog lights are designed only for seriously reduced visibility, typically below 100 metres, such as in thick fog, heavy rain, or snow. Using them when conditions don’t require it is an offence under the Road Vehicles Lighting Regulations 1989.

If you are caught driving with your fog lights on when it’s not necessary, you could face a fine. While the exact penalty can vary, a £40 fine is common for this offence. To avoid penalties and ensure safety on the road, always remember to turn off your fog lights when visibility improves.

If your fog light switch, wiring, or bulbs aren’t working properly, have them checked by a qualified mechanic to avoid accidental misuse.

Which dashboard symbol is for fog lights?

In your car, the dashboard will display a different symbol for the front fog lights versus the rear ones.

For front fog lights, the symbol typically appears as a lamp facing left with three horizontal lines crossing through a wavy vertical line. When this symbol illuminates green, it means the front fog lights are activated.

For rear fog lights, the symbol looks similar but shows the lamp facing right. It will light up in amber or yellow on your dashboard when the rear fog lights are on. Rear fog lights are mandatory in the UK and should be used to alert other drivers behind you when visibility is severely reduced.

If you're ever unsure about any dashboard symbols, refer to your car’s owner's manual for clarification. Proper use of your fog lights is important for safety and ensuring you comply with UK driving laws.

What does a fog light replacement job involve?

When your fog lights need replacing, the mechanic generally follows this process to ensure everything is fixed correctly:

• The mechanic checks the fog light bulb or LED unit, wiring, fuses, and connectors to pinpoint the cause of the failure. This helps determine whether the issue is with the light itself or the electrical circuit.

• If the bulb, LED module, or complete fog light housing is damaged, it’s removed and replaced with a manufacturer-approved part. For front fog lights, this may involve removing part of the bumper or wheel-arch lining for access.

• Once the replacement is complete, the fog lights are tested to ensure they illuminate correctly and that the dashboard fog light symbol comes on as it should. The mechanic may also check your other exterior lights for safety.

How do I know when I need a fog light replacement?

​​The signs that your fog lights may need replacing are fairly simple:

• The most obvious sign is no illumination when you switch the fog lights on. This could be due to a blown bulb, failed LED unit, wiring issue, or a faulty switch.
• When you activate your front or rear fog lights, a matching symbol should appear on your dashboard. If the light stays off, the fog light itself or the circuit may not be working.
• Flickering fog lights often point to worn bulbs, loose wiring, or moisture inside the fog light housing. If one fog light appears noticeably dimmer than the other, the bulb may be failing or the lens may be damaged or fogged internally.
• Physical damage or condensation inside the fog light assembly can quickly lead to bulb failure or short circuits.

Additionally, in the UK, cars must have at least one working rear fog light. If it’s not functioning, it will be flagged during an MOT.If you notice either of these symptoms, it's important to get the fog lights checked and replaced to ensure your visibility and safety, especially during adverse weather conditions.

How much does a fog light replacement cost?

The cost of replacing a fog light varies depending on factors such as your vehicle's make and model, as well as the type of fog light required. On average, fog light replacement costs in the UK range from £65 to £185. For example, replacing a fog light on a more common vehicle like a Vauxhall may cost around £65, while replacing one on a premium vehicle like a Land Rover could be closer to £185.
Use our free price estimator tool to find out what you could save by having your fog light replaced by ClickMechanic!

What does a ClickMechanic fog light replacement quote cover?

Unless otherwise stated, the quote will cover:

• The cost of the fog light
• Coming to you
• Fitting of the parts
• Disposal of the old parts (unless you request to keep them)
• VAT (if applicable)
• 12-month parts and labour warranty

Can a mobile mechanic replace the fog light?

Yes, a mobile mechanic can usually replace a fog light without needing to take your car to a garage. Since fog lights are accessible from either the front or rear of the vehicle, depending on the design, replacing them is generally a straightforward task that doesn’t require a garage environment. A mobile mechanic can come to your home or workplace, inspect the fog light unit, and fit a replacement if needed.