MOT & Your Car's Lights Explained

It's a common point of confusion for many motorists: if your car has a functioning light bulb, does that automatically mean it's road legal and will pass its MOT? While having a working bulb is certainly a step in the right direction, the reality is a little more nuanced. The regulations governing vehicle lighting and the requirements for an MOT are, as the saying goes, a 'completely different kettle of fish'. This article aims to demystify these regulations, explaining what makes your car's lights road legal and what specific aspects are scrutinised during an official MOT test.

Understanding Road Legal Lighting

The fundamental principle of road legality for vehicle lighting is laid out in the Road Vehicles Lighting Regulations. These regulations are comprehensive and cover a wide array of requirements to ensure that all vehicles on UK roads are adequately and safely lit. Key aspects include:

• E Marking/Approval: For many lighting components, especially those fitted as original equipment or as replacements, they must bear an 'E' mark. This mark signifies that the component has been tested and meets European safety and performance standards. This is a crucial indicator of compliance.
• Correct Wattage: Each lighting function (headlights, brake lights, indicators, etc.) is designed to operate with a specific wattage bulb. Using a bulb with the incorrect wattage can lead to several problems. Too low a wattage might result in insufficient illumination, while too high a wattage could overheat the wiring, melt the light housing, or even damage the vehicle's electrical system. It's vital to use bulbs that match the manufacturer's specifications.
• Type Approval: Similar to the E marking, some components may have type approval certificates. This further confirms that the part has met stringent design and performance criteria.
• Functionality: At its most basic, a light bulb must be capable of illuminating. A blown bulb, or one that is significantly damaged, will not meet the functional requirement.

These regulations are in place to ensure that your lights are not only visible to other road users but also that they illuminate the road ahead effectively and safely, without causing undue glare or distraction. For instance, headlights must project a beam pattern that illuminates the road ahead without dazzling oncoming drivers. Similarly, brake lights must be bright enough to be seen clearly by following traffic, even in daylight conditions.

What Does the MOT Test Actually Check?

Now, let's turn our attention to the MOT test. While the Road Vehicles Lighting Regulations dictate what is required for a vehicle to be legally used on public roads, the MOT test has a specific, defined set of checks that it performs. Crucially, the MOT test does not check for the presence of an E mark or the correct wattage of a bulb in the same way as the lighting regulations. Instead, the MOT test focuses on the functionality and condition of the lights.

During an MOT inspection, the tester will specifically examine:

• Operation: They will check that each required light operates correctly. This includes headlights (both main beam and dipped beam), front and rear position lights, brake lights (including the high-level brake light if fitted), hazard warning lights, and rear fog lights and reversing lights (if fitted).
• Condition: The physical condition of the light units is also assessed. This means checking for cracks, damage, or deterioration that could prevent the light from functioning correctly or obscure its beam. A cracked headlight lens, for example, might allow moisture in, leading to corrosion or bulb failure, and could also affect the beam pattern.
• Aim/Alignment: For headlights, the aim (or alignment) is a critical component of the MOT. The beam must be directed correctly to illuminate the road without dazzling other drivers. Testers use specific equipment to ensure the headlights are within the acceptable limits for both horizontal and vertical aim.
• Colour: The colour of the light emitted is also checked. For example, headlights must emit white light, front side/position lights must be white, rear lights must be red, and indicators must be amber. Any deviation from these colours can lead to an MOT failure.
• Visibility of Markings: While not checking the E mark itself, the tester will ensure that any mandatory markings are visible and that the light unit is not obscured by aftermarket tints or covers that would prevent it from being seen.

The Difference: Road Legal vs. MOT Pass

This distinction is important. You could have a bulb that is E-marked and the correct wattage (therefore road legal), but if it's not working, or the light unit is badly damaged, it will fail the MOT. Conversely, you might have a bulb that isn't E-marked or is the wrong wattage, but if it illuminates correctly and the unit is in good condition, it might technically pass the MOT's functional check. However, it is still illegal to use such a vehicle on the road.

The key takeaway is that to be truly compliant, your vehicle's lighting must meet both the Road Vehicles Lighting Regulations AND the MOT test requirements.

Common Lighting Issues and MOT Failures

Lighting is a very common reason for MOT failure. Here are some of the most frequent culprits:

Frequently Asked Questions

Q1: Do I need an MOT if my car is over 40 years old?
As of 20th May 2018, vehicles that are more than 40 years old and have had no substantial changes made to them are exempt from the MOT test. However, if a vehicle is less than 40 years old, it still requires an MOT.

Q2: Can I use coloured bulbs in my headlights?
No. Headlights must emit white light. Using coloured bulbs is illegal and will result in an MOT failure.

Q3: What happens if my brake light bulb is out?
A faulty brake light is a dangerous defect and will cause your vehicle to fail its MOT. It also makes your vehicle illegal to drive on the road, so it should be replaced immediately.

Q4: Do I need to check my hazard lights for the MOT?
Yes, the hazard warning lights are tested during the MOT to ensure they operate correctly and all indicators flash simultaneously.

Q5: My car passed its MOT, but a bulb has gone out since then. Is it still legal to drive?
While your car passed the MOT, the law still requires all lights to be in working order. If a bulb has failed since the test, your vehicle is no longer road legal, and you should get it fixed as soon as possible to avoid potential fines or issues if stopped by the police.

Conclusion

In summary, while having a light bulb fitted is a prerequisite for any light to function, the specific regulations for road legality are more detailed than simply having a bulb present. The Road Vehicles Lighting Regulations dictate the type, marking, and wattage of bulbs and the performance of the lighting system. The MOT test, on the other hand, primarily assesses the functionality, condition, aim, and colour of these lights. To ensure your vehicle is both road legal and passes its MOT, it's essential to adhere to the lighting regulations and maintain your vehicle's lighting system in good working order. Regular checks of all your car's lights are a simple yet vital part of vehicle maintenance.

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