Car Lights & MOT: Are Sidelights Tested?

Driving on UK roads demands not only skill but also a vehicle that is in prime condition, especially when it comes to lighting. Proper illumination is paramount for your safety, the safety of other road users, and for passing the annual MOT test. From the subtle glow of your sidelights to the powerful throw of your full beams, every light serves a crucial purpose. But do you truly understand what each light does, when to use it, and, critically, what the MOT examiner is looking for? Let's shed some light on these essential components of your car.

Are Sidelights Tested During an MOT? Absolutely.

One of the most common questions we hear is, 'Are sidelights tested during an MOT?' The answer is a resounding yes. Sidelights, also known as parking lights or position lamps, are fundamental to your vehicle's visibility, particularly during twilight hours or when parked at the side of a road at night. During an MOT, the examiner will meticulously check several aspects of your sidelights:

• Presence and Operation: All required sidelights must be present and correctly working. Typically, this means two white lights at the front and two red lights at the rear.
• Colour: The front sidelights must emit white light, and the rear ones red light. Any deviation from these colours will result in a failure.
• Condition: The lenses must be clean, unbroken, and securely fitted. Cracks or damage that significantly impair light output or change its colour will lead to a fail.
• Pairing: If your vehicle has a pair of sidelights, both must be working. A single faulty light in a pair is a reason for failure.

Ensuring your sidelights are in perfect working order is a simple check that can save you from an MOT retest.

Understanding Full Beam Headlights

Beyond your standard dipped headlights, your vehicle is equipped with a more powerful lighting option: full beam headlights. These are the brightest type of headlight on normal vehicles and are sometimes known as high beams. They are specifically designed to provide maximum illumination, angled higher than dipped headlights to allow you to see further down the road, making them indispensable when driving on unlit roads at night.

The switch to activate your full beams is usually located near the control for your dipped headlights, often integrated into the indicator stalk. While some vehicles use the same bulbs for both dipped and full beam, others employ a separate set, designed for the higher intensity output.

It's crucial to use full beams responsibly. They are intended for use when there is no oncoming traffic and no vehicle directly ahead of you, ensuring you don't dazzle other drivers. Failing to switch back to dipped beams in appropriate situations is not only inconsiderate but also incredibly dangerous, significantly increasing the risk of an accident. Always dip your headlights when approaching other vehicles or when driving in well-lit areas.

Understanding Headlight Dazzle: A Blinding Problem

Headlight dazzle is a phenomenon that most drivers have experienced – that blinding effect caused by an oncoming vehicle's headlights. It's not just a nuisance; it's a distressing and potentially dangerous aspect of night-time driving that can temporarily impair a driver's vision, leading to delayed reactions and an increased accident risk. You've probably been exposed to this whilst driving at night, and it's a concern that affects countless motorists across the UK.

What Causes This Blinding Glare?

The issue of headlight dazzle is far more complex issue than simply blaming 'bright lights.' As Rod Dennis, spokesman for the RAC, explains, "Among some drivers there is a perception that newer headlights cause more glare. But while a sizeable proportion claim it is the xenon headlights more often found in higher-end vehicles that are primarily to blame, a greater proportion either don’t know the difference between lights or aren’t sure."

He elaborates further: "In reality, the issue of glare is a complex one and it’s not as straightforward as saying one type of lightbulb causes more of a dazzling effect than another – there are a range of reasons why a driver might be dazzled, from a slight misalignment of a headlight, the difference in ride height of different vehicles and even individual people’s vision. That explains why not every car headlight appears to be dazzling, with eight-in-10 drivers saying only some cause glare."

Common causes include:

• Misalignment: Even a slight deviation in a headlight's aiming can direct its beam into the eyes of oncoming drivers. This can happen due to minor bumps, vibrations, or incorrect adjustment after maintenance. A properly aimed headlight projects light onto the road, not into oncoming traffic.
• Vehicle Load and Ride Height: A heavily loaded boot or rear seats can lift the front of a car, tilting the headlights upwards. Similarly, higher-riding vehicles like SUVs or vans naturally have their lights positioned higher, which can appear more dazzling to drivers in lower-slung cars. Many modern cars have manual or automatic headlight levelling systems to counteract this, but they must be used or functioning correctly.
• Individual Vision: Drivers with certain eye conditions, older drivers, or those with astigmatism may be more susceptible to glare. This is a factor beyond the vehicle's control but contributes to the overall problem.
• Light Technology: While newer technologies like Xenon (HID) and LED lights are inherently brighter and offer superior road illumination for the driver, their intensity can be perceived as more dazzling if not correctly designed, installed, and aimed. Halogen lights, too, can cause dazzle if misaligned or if cheap, unapproved bulbs are used.

Are Bright Headlights Illegal in the UK?

Surprisingly to many, the brightness of headlights themselves isn't typically illegal, provided they meet specific international standards. However, as Dennis points out, "All headlights have to meet specific international standards, which motorists might be surprised to discover haven’t been updated since the 1960s and so do not take specific account of newer technologies like xenon and LED." This aging regulation is a significant concern for the majority of surveyed drivers in the RAC Report on Motoring, who feel the rules haven't kept pace with technological advancements. The key is not just brightness, but how that brightness is controlled and directed onto the road, preventing it from causing glare.

Am I Causing Headlight Glare Myself?

It's a question many drivers consider, and it's certainly possible. The RAC advises that you could be contributing to headlight glare if:

• Your Headlights are Misaligned: This is the most common culprit. Even a minor bump or incorrect re-fitting can knock them out of alignment. Regular checks, especially after any front-end work, are advisable.
• Your Vehicle is Overloaded: Carrying heavy items in the boot can tilt your car backwards, pointing your headlights upwards. Always adjust your headlight levelling control if your vehicle has one, especially when carrying heavy loads.
• You've Installed Aftermarket Bulbs Incorrectly: While upgrading bulbs can seem appealing, ensure they are E-marked (European approved) and compatible with your car's headlight unit. Incorrectly fitted or unsuitable bulbs can scatter light excessively, creating glare and potentially failing an MOT.
• Your Headlight Lenses are Dirty or Scratched: A build-up of dirt, grime, or significant scratching on the lens can diffuse light, causing more scatter and glare. Keeping your headlight lenses clean and clear is a simple yet effective way to improve light output and reduce dazzle.

Regular checks and maintenance are vital not only for your MOT but also for the safety and comfort of everyone on the road.

Comprehensive MOT Light Checks

The MOT test is incredibly thorough when it comes to vehicle lighting. While we've focused on sidelights, full beams, and dazzle, it's important to understand that all lights on your vehicle are scrutinised. Here’s a breakdown of what the MOT examiner checks:

• Headlights (Dipped & Full Beam):
  • Presence, operation, and security.
  • Correct colour (white/yellow).
  • Correct aim – this is crucial for preventing dazzle and ensuring adequate road illumination.
  • Lens condition – no cracks, chips, or discolouration that significantly impairs light output.
  • Correct switching – dipped and full beam must switch correctly, and a main beam warning light must operate on the dashboard.
• Sidelights/Position Lamps: (As detailed above) Presence, operation, colour, condition, pairing.
• Brake Lights:
  • All required brake lights (usually two, plus a high-level third light on newer cars) must work.
  • Must illuminate when the foot brake is applied.
  • Correct colour (red).
  • Condition and security.
• Indicators/Direction Indicators:
  • All indicators must work and flash at the correct rate.
  • Correct colour (amber).
  • Condition and security.
  • Hazard warning lights must also operate correctly.
• Rear Fog Lights:
  • Must be present (one or two, depending on vehicle design) and operate.
  • Must be red.
  • Must have an illuminated warning light on the dashboard when activated.
• Number Plate Lights:
  • All lamps illuminating the rear number plate must work.
  • Must emit white light to make the number plate clearly legible at night.
• Reflectors:
  • Rear reflectors must be present, secure, and the correct colour (red).
  • Not damaged or obscured.

Any failure in these areas will result in an MOT fail, often requiring immediate repair before a retest can be passed. It highlights the importance of regular pre-MOT checks and proactive maintenance to avoid inconvenience and ensure your vehicle is safe.

Types of Headlights and Their Characteristics

Frequently Asked Questions About Car Lighting & MOT

Q: Can I fail my MOT for a blown bulb?

A: Yes, absolutely. Any non-functioning bulb that is part of the mandatory lighting system (headlights, brake lights, indicators, sidelights, number plate lights, fog lights) will result in an MOT failure. It's one of the most common and easily preventable fails, highlighting the importance of a quick check before your test.

Q: Do I need to have my headlights professionally aligned?

A: While minor adjustments can sometimes be made by a confident DIYer, professional alignment using specialist equipment (a beam setter) is highly recommended. This ensures your lights are aimed precisely to illuminate the road effectively without dazzling other drivers. It's especially important if you suspect your lights are causing dazzle or if you've recently had work done on your vehicle's front end or suspension.

Q: What about aftermarket LED or Xenon bulbs in halogen housings?

A: This is a tricky area and generally not advisable. Fitting LED or Xenon bulbs into a headlight unit designed for halogen bulbs is typically illegal and will almost certainly fail an MOT. These conversions rarely provide the correct beam pattern, leading to excessive glare for other drivers and often insufficient, scattered illumination for you. Furthermore, factory-fitted Xenon/LED units require automatic levelling and headlight washer systems, which aftermarket conversions usually lack.

Q: Is a cracked headlight lens an MOT failure?

A: It depends on the severity. A minor chip or crack that doesn't significantly impair light output, allow moisture ingress, or noticeably change the beam pattern might be an advisory. However, a crack that significantly affects the light's colour, distorts the beam, or compromises the security of the lamp will be an MOT failure. The lens must be secure and not pose a safety hazard.

Q: What should I check before taking my car for an MOT regarding lights?

A: Before your MOT, perform a quick visual check:

1. Turn on your sidelights, dipped beam, and full beam. Walk around the car to ensure all are working, including front and rear.
2. Test your indicators (left, right, and hazards) – check all four corners and the dashboard warning light for correct flashing speed.
3. Ask someone to press the brake pedal while you check all brake lights (usually two main and a high-level one).
4. Engage reverse gear (with the engine off and handbrake on for safety) and check reverse lights.
5. Turn on your rear fog light and check the dashboard warning light.
6. Ensure your number plate lights are working.
7. Check all lenses for dirt, cracks, condensation, or discolouration.
8. If your car has manual headlight levelling, test that it works through its range.

This simple check can save you time, money, and the hassle of an MOT retest.

Conclusion

Understanding your vehicle's lighting system goes far beyond simply knowing how to switch your headlights on. From the essential sidelights that keep you visible to the powerful full beams designed for maximum illumination, and the complex issue of headlight dazzle, every aspect plays a critical role in road safety and MOT compliance. Regular checks, responsible usage, and ensuring your lights are correctly aimed and functioning are not just about passing a test; they are about safeguarding yourself and others on the road. Drive safe, drive illuminated, and ensure your vehicle is always roadworthy.

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