Brake Light change, repair & replacement made easy

How does a brake light work?

Your brake lights are an essential safety feature that let other drivers know when you’re slowing down or stopping. When you press the brake pedal, a small brake light switch completes an electrical circuit, instantly sending power to the rear brake lights so they illuminate and alert traffic behind you.

Most cars have two rear brake lights, and modern vehicles also feature a third, high-mounted brake light for better visibility. These can be separate units or part of a rear light cluster that also includes indicators, reverse lights, and tail lights but they do all share the same purpose: improving safety by warning other road users.

Because brake lights rely on electrical connections and working bulbs (or LEDs), they can fail due to burnt-out bulbs, faulty wiring, or a failed brake light switch. If your brake lights stop working, it’s important to have them checked and repaired by a qualified mechanic to stay safe and comply with UK road regulations.

What does a brake light replacement job involve?

Here’s how a qualified mechanic typically performs a brake light replacement:

• The mechanic checks all rear lights to confirm which bulb, LED unit, or connection is faulty. They may also test the brake light switch to rule out electrical issues.
• Depending on your vehicle, the rear light cluster or boot lining is removed to reach the faulty bulb or LED assembly.
• The defective bulb is carefully twisted or unclipped from its socket. For LED systems, the entire light unit may need replacing.
• A new, manufacturer-approved bulb or light unit is fitted, ensuring a proper seal and electrical connection to prevent water ingress or flickering.
• The mechanic presses the brake pedal (or uses a helper) to confirm that all brake lights illuminate evenly and at the correct brightness.
• Other lights in the same cluster, such as tail, indicator, or reverse lights - are often tested to ensure the whole system is working correctly.

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

Because brake lights are behind you, it’s easy to miss when one stops working. Still, there are several signs that can help you spot a failing brake light before it becomes a safety issue:

• No illumination when braking: The most obvious sign is that one or more of your brake lights don’t come on when you press the pedal. You can check this by asking someone to stand behind the car or by reversing near a reflective surface.
• Brake warning light on the dashboard: Some modern vehicles monitor the lighting circuit and will trigger a dashboard alert if a bulb or LED unit fails.
• Uneven brightness: If one brake light looks dimmer than the other, the bulb could be wearing out or the socket may have corrosion affecting the connection.
• Fast-flashing indicators or lighting faults: On some cars, the indicator flashes faster when a bulb in the same cluster has failed, signalling an issue with the electrical system.

If you notice any of these signs, it’s best to replace the faulty brake light as soon as possible.

Is it illegal to drive with a brake light out in the UK?

Yes, driving with a faulty or non-working brake light is illegal in the UK. It’s a safety offence under the Road Vehicles Lighting Regulations 1989 and can result in a fine, penalty points, or a defect notice.
If the police stop you and find that a brake light isn’t working, you could receive a Vehicle Defect Rectification Notice, which gives you 14 days to fix the problem and show proof of repair. In some cases, you may be issued a £60 fixed-penalty fine and three points on your driving licence. More serious cases, especially if the fault contributes to an accident, can lead to higher penalties in court.

For your MOT test, a single non-working main brake light is treated as a minor fault (advisory), meaning it won’t cause an automatic fail but still needs attention. However, if the third (high-level) brake light is fitted and fewer than half of its LEDs work, that may cause an MOT failure.

To stay safe and avoid legal trouble, check your brake lights regularly. If you notice a blown bulb, cracked lens, or wiring issue, have it repaired by a qualified mechanic to keep your car road-legal.

How much does a brake light replacement cost?

A brake light replacement typically costs between £90 and £180, with the average job around £140. The exact price depends on your vehicle’s make and model and the specific brake light units your manufacturer recommends. Use our free price estimator tool to find out what you could save by having your brake light replaced by ClickMechanic.

What does a ClickMechanic brake light replacement quote cover?

Unless otherwise stated, the quote will cover:

• The cost of the brake lights
• 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 brake light?

Yes, a mobile mechanic can replace a brake light without the need for a garage visit. Most brake light replacements are straightforward and don’t require specialist equipment that’s only available in a workshop. A qualified mobile mechanic can come to your home or workplace with the necessary tools and parts to diagnose the issue, remove the faulty unit or bulb, and fit a new one.