Headlight Checks in MOT Tests

The Importance of Headlights in Your MOT Test

The MOT test is a vital annual inspection designed to ensure your vehicle is safe and compliant with roadworthiness standards. While many drivers focus on brakes, tyres, and emissions, the condition and functionality of your headlights are equally critical. Failing to have properly functioning headlights can not only lead to an MOT failure but also pose a significant safety risk, especially during adverse weather conditions or nighttime driving. This article delves into why headlights are so rigorously checked during an MOT and what specific aspects inspectors examine.

Legal Requirements for Vehicle Lighting

In the United Kingdom, driving with faulty or inadequate lighting is a breach of the Road Vehicles Lighting Regulations 1989. These regulations dictate the types of lights a vehicle must have, their colour, intensity, and how they should be used. The MOT test serves as a primary mechanism to enforce these regulations, ensuring that all vehicles on the road meet a minimum safety standard. Proper illumination is paramount for visibility, both for the driver to see the road ahead and for other road users to see your vehicle.

What Inspectors Look For: A Detailed Breakdown

During an MOT, the vehicle examiner will conduct a thorough inspection of your headlights, assessing several key areas:

1. Functionality and Operation

This is the most basic, yet essential, check. The examiner will test each light function to ensure it operates correctly. This includes:

• Dipped Beam (Low Beam): This is the primary headlight used in normal driving conditions. It must illuminate the road ahead without dazzling oncoming drivers.
• Main Beam (High Beam): Used on unlit roads when there is no oncoming traffic. It must be able to be switched on and off effectively.
• Parking Lights: These are used when the vehicle is parked.
• Indicator Lights (Turn Signals): Front and rear indicators must flash correctly and be the appropriate colour (amber).
• Hazard Lights: These must operate all theigator lights simultaneously.

Failure to have any of these lights working correctly will result in an MOT failure.

2. Aiming and Alignment

The angle at which your headlights are aimed is crucial. If they are aimed too high, they can dazzle oncoming drivers, creating a dangerous situation. If they are aimed too low, they won't illuminate the road sufficiently, hindering your ability to see hazards. The MOT test includes a check for correct headlight aim. This is often done using a specialised "headlight aim tester" which measures the beam pattern and its alignment on a screen.

Factors affecting headlight aim include:

• Suspension Wear: Worn suspension components can cause the vehicle's ride height to change, subsequently altering headlight alignment.
• Incorrect Bulb Fitment: If bulbs are not seated correctly in their housings, the beam pattern can be distorted.
• Damage to Headlight Housings: Cracks or damage can affect the positioning of the reflector and lens.

Incorrect headlight aim is a common reason for MOT failure.

3. Condition of the Headlight Units

The physical condition of the headlight units themselves is also assessed. This includes:

• Cracks and Damage: Any significant cracks or damage to the headlight lenses can affect the light output and beam pattern, and may allow moisture to enter, damaging the bulb and reflector.
• Discolouration or Hazing: Over time, plastic headlight lenses can become cloudy or yellowed due to UV exposure and oxidation. This significantly reduces light output and can cause an MOT failure if it obstructs the light beam. Many modern cars have plastic lenses that are prone to this.
• Corrosion: While less common with modern materials, corrosion can affect the reflector within the headlight unit, reducing its effectiveness.

Damaged or hazed headlight units can lead to an MOT failure.

4. Bulb Type and Colour

The MOT test also ensures that the correct type of bulbs are fitted and that they emit the correct colour of light. For dipped and main beams, the light must be white. Front side and indicator lights must be white or amber respectively. Rear lights must be red, and brake lights must be red. Using aftermarket bulbs that emit blue or overly bright white light can lead to a failure.

Incorrect bulb types or colours are a definite cause for rejection.

5. Headlight Washers and Levelling Systems (if fitted)

Vehicles equipped with headlight washers and self-levelling systems (often found on cars with Xenon or LED headlights) must have these systems functioning correctly as part of the MOT test. These systems are designed to maintain optimal visibility and prevent dazzling. If your car has these features, they will be checked.

Non-functioning headlight washers or levellers will result in a failure.

Common Reasons for Headlight Failure in MOT Tests

To help you prepare for your MOT, here are the most frequent reasons why headlights fail:

Tips for Passing Your MOT Headlight Check

Before taking your car for its MOT, it’s a good idea to perform a quick check of your headlights yourself:

• Test all functions: Turn on your dipped beam, main beam, and indicators. Ensure all bulbs are working and flashing correctly.
• Check for hazing: Look at your headlight lenses. If they appear cloudy or yellowed, consider cleaning or polishing them. There are many DIY kits available, or you can seek professional help. This can make a significant difference to light output and appearance.
• Inspect for damage: Check for any cracks or chips in the lenses. Minor damage might be acceptable, but significant damage could lead to a failure.
• Consider professional alignment: If you suspect your headlights might be misaligned (e.g., you notice you can't see as well at night, or other drivers seem to be flashing their lights at you), it's worth having them checked and adjusted by a mechanic before the MOT.

Frequently Asked Questions (FAQs)

Q1: Can I fail my MOT for having HID or LED bulbs fitted if they weren't original?
Yes, if your vehicle was not originally equipped with HID or LED headlights, and they have been retrofitted, they may fail the MOT if they do not meet specific ECE regulations for aim, intensity, and the presence of self-levelling and washing systems. The colour of the light is also critical; it must be the correct shade of white.

Q2: My headlights are a bit cloudy, will this cause a failure?
It depends on the severity. If the hazing is minor and does not significantly obstruct the light output or alter the beam pattern, it may pass. However, if the lenses are significantly opaque or yellowed, reducing visibility, it will likely result in a failure.

Q3: What if one of my headlights is out?
If one of your main headlights (dipped or main beam) is not working, your vehicle will fail the MOT. All essential lights must be operational.

Q4: How can I check my headlight aim without special equipment?
While a professional check is recommended, you can get a rough idea by parking your car on a level surface facing a wall. Turn on your dipped beam and observe the pattern. The brightest part of the beam should be roughly level with the centre of the headlight, and it should have a distinct cutoff line. However, precise alignment requires specialised equipment.

Q5: Do I need working headlight washers for my MOT?
Only if your vehicle was originally fitted with them. Headlight washers are a mandatory item to check if your car has Xenon or LED headlights, as these systems are required by law to ensure the lights remain clean and effective. If they are fitted, they must work.

Conclusion

Your headlights are more than just a cosmetic feature; they are a critical safety component. Ensuring they are clean, correctly aimed, and fully functional is essential for passing your MOT test and, more importantly, for your safety and the safety of others on the road. Regular checks and prompt attention to any issues will help ensure your vehicle remains roadworthy and compliant.

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