/ Motoring

Are both your car headlights working?

It’s still dark and dull outside, and so driving conditions aren’t all that great. Being visible on the road is not just important, it’s a legal requirement. So are both of your car headlights working?

On 27 January we reported that, according to government figures, nearly half of MOT failures last year would have been avoidable had the vehicle owner carried out a few basic visual checks in advance. And of those checks, simple lighting faults accounted for one in five of these cases.

While headlight failures may seem like just a minor inconvenience for some, it’s an irritation of mine. And based on the evidence I’ve seen while driving lately, it’s a problem that seems to be frequently slipping through the net. So I think it’s time to shine a light on the issue.

Under the spotlight

Now, you’d probably notice if both your car headlights were out, especially if you drive at night. But only losing one headlight might pass you by. Well-lit streets can hide the effect from the driver. Some may even be aware, but don’t see the issue as serious enough to deal with it straight away.

But vehicles with only one working light will appear to be considerably smaller than they actually are when viewed head-on and in mirrors by other drivers – you can end up believing that you have a motorbike in your vicinity, when in fact it’s a full-sized car or van.

In some cases the one working light will itself be obscured, leading the driver to assume there are no other vehicles around them at all, which could have serious consequences when it comes to turning, braking and changing lanes.

Not to mention the issues that could arise from any unfortunate collisions. If a headlight being out was the cause of the accident, how could you prove that the faulty headlight was broken before impact?

The fact is that driving without working headlights is an MOT failure, and it’s a failure for a reason – when visibility is poor it’s fundamentally dangerous for other drivers as well as pedestrians.

Here’s a bright idea

Now changing a car bulb can be an easy task on some car models, and a little trickier for others. A replacement bulb will usually cost you less than £5, and you may have to pay a further £5 to £10 if you require someone to fit it for you. But, all in all, I think it’s a pretty fair price to pay, that far outweighs the risk of not being seen on the road.

The number of vehicles I’ve spotted lately with partially or fully blown headlights on one side has been quite alarming, and I find it hard to believe that this problem could be localised (south London, for those wondering).

So, have you checked your headlights recently? And, have you, like me, noticed an increase in cars with their headlights out? Why do you think this is?


No doubt in the light (!) of this Conversation I have been looking at day-running lights while out and about on foot in the last few days. There have been many comments on the rather silly-looking chains of LED’s that are now adorning many new cars and drawing attention to their ugly front-end design. The best looking seem to be on BMW’s where they are integrated with the headlight module and appear as a concentric circle, not dazzling, and looking like the good engineering they should be. Time for other manufacturers to drop the pretentious and glaring string-of-fairy-lights effect and make lights that perform well, have easy-to-replace bulbs, and project the right amount of light in the most appropriate direction according to the prevailing conditions.

I am accustomed to new cars looking unfamiliar but cannot recall ever seeing so many ugly new cars. Hopefully DRLs will become less silly when the novelty wears off.

We now have mood lighting appearing in some cars. At present it’s confined to interior lights but I’m sure the manufacturers will be keen for us all to appreciate how clever they are if they can get away with pretty coloured exterior lighting.

The car remains an important status symbol – well, at least the manufacturers think it should which is why they are constantly trying to tweak the styling and glamourise the shape in the hope of appealing to a particular market segment. The advertising seems to be directed mainly at 20-30 year olds [the PCP purchase arrangements help in this respect] even though this group is usually more concerned about getting a roof over their head and raising a family. By the law of averages, most drivers are in an older vehicle, usually second- or third-hand; they must regard the new models which will be in their price bracket in three-four years’ time with a degree of apprehension if they want something practical, manageable and maintainable.

Nowadays you are no-one if you don’t have a quality or executive car with automatic adjustment of seats and other ego-massaging features. Perhaps it would be more useful to issue a reminder to look check the lights etc. The driver could be rewarded with an nice tune once they had complied.

I like that. Traffic signals, before they went LED, used to have a second lower wattage bulb that activated if the primary lamp failed – I am surprised this hasn’t been introduced in cars, not for the driver’s convenience but to ensure that two lights are always showing to oncoming vehicles.

I haven’t tried auto-adjusting seats; do they have a personal memory with pre-sets for the wife, the M-i-L, and other regular passengers? What I would appreciate in all cars is auto-adjusting head-rests in the rear seats as they always seem difficult to get right and some car owners don’t like people playing with them so they keep them at the lowest possible level which apart from being uncomfortable is illegal if the back of the head does not align with it.

DRL’s aren’t adorning ‘many’ new cars. They’re adorning ‘all’ new cars. As of February 2011 it has been mandatory for all new vehicles to have DRLs in order to pass type approval.

I appreciate that Will. I was specifically referring to the ribbons of LED lights that have been designed into many new cars as their compliance with the regulations. Other cars, and I particularly mentioned BMW’s, have much more sensible DRL’s.

vehicles are now designed that you have to take them to a garage/mechanic so the garage also makes money out of you -another rip off! Of for the good old days (retired mechanic)

Around South Yorkshire, I find there is a direct correlation between vehicles with defective lights and drivers intent of showing the rest of us how good they are at ignoring traffic laws and etiquette in general.

I haven’t had to change a bulb on my own car for a few years but I have on my wife’s Fiesta and that requires the removal of the headlamp unit; not something you want to do on the side of the road.

I used to fit bulbs for Halfords. Firstly I’d like to say that Halogen technology – which is more than 95% of all vehicle bulbs you see on the road today, recognisable by the distinctive yellow-hue glow – are awful. They’re a budget technology with terrible reliability. To make matters worse, if the person installing them touches bare skin to the glass, oil contamination can cause premature failure – it reacts with the gas inside the bulb in a certain way.

Secondly, yes, changing bulbs is a horrible pain on many cars. Whilst I’ve often joked that manufacturers do this to try and force you to go a garage, the simple truth is modern cars are all about cramming as much technology as possible into as much empty space as possible. I’ve never had to take the battery out to change the passenger bulb before, but I have on various occasions – some models of Ford Focus, etc – had to unscrew the headlight cluster and bits of trim panel, and even then I’ve had to contort my hand to reach the bulb.

Halogen bulbs aren’t just unreliable; they’re inadequate. Light spread is poor. At the very least, HiD (Xenon) bulbs are way better. Sure, they’re ten times more expensive, but they have far higher reliability, far higher performance, and produce a crisp white light that is much better at highlighting potholes. LED bulbs are even better than that, albeit super expensive at the moment. LED bulbs are the ultimate future of headlights because they can dim in localized areas around the car in front, oncoming cars or pedestrians, but remain fully lit elsewhere, allowing you to leave them on full beam without blinding other road users.

Since the EU like to meddle in everything, surely the answer to the labour cost of replacement is to get them to mandate that all required bulbs (i.e. those required by law) can be changed at the roadside without the use of tools. A time limit of say 5 minutes for changing any bulb would ensure that manufacturers designed the vehicle accordingly. We could then adopt the old French system of making all drivers carry a spare of each bulb. How Renault could design a car where you have to remove the front wing to replace a headlamp bulb is beyond me.
In 1977 I had a new Vauxhall Cavalier & was very pleased to find that all bulbs at the rear were fitted in a tray that could be easily removed by wing nuts. About 2 minutes was all it took to change any of the bulbs. It wasn’t difficult to design the car that way then & shouldn’t be now.

The lights on my wife’s car are checked every week as it only goes out twice on regular basis.
My car is checked every time I use it due to a large window behind me and my neighbours window in front of me, also my grandchildren have a thing about checking my lights after they witnessed me changing a rear bulb and I explained why it had to be replaced and they don’t want the police man to shout at me.
I am however fed up seeing cars with only 1 stop/brake light or a side light and headlamp out on the same side of the vehicle.
I believe these people should be prosecuted for failing to maintain a road vehicle as 2 or more bulbs do not usually fail at the same time.
Owners have a legal requirement to check ALL the lights on their vehicle before use and you may not use a defective vehicle on the public highway. Yet you will all b***h like hell if you was booked for it.
I have changed failed bulbs on motorway services before now especially if I was to be away for the week as a mobile crane engineer, covering over 150,000 mile a year for over 25 years.
Regards front and rear fog lamps, the clue is in the word **FOG**.
Front FOG lamps may only be used in FOG or Falling Snow.
Rear FOG lamps may only be used in FOG with the visibility of less than 100 metres, NOT RAIN

Last week I found myself behind a car with a working number plate light but no tail lights. We were approaching traffic lights so I pulled into the other lane, wound down the window and shouted to alert him to the problem. He thanked me but was still driving without lights when I turned off a mile further on.

Thanks George. A simple post like this provides encouragement because we have no idea of which topics are being pursued.

Wavechange if there was two of you in the car (you did post “we”) your passenger could have taken his number and you could have reported him to the police who in turn, could have traced the offender through the DVLA. Problems arise when you are the sole occupant and like me, your short term memory may not be as good as it used to be 🙂

Now that vehicles with Daylight Running Lamps are more common, I notice many with only one illuminated. This is strange, since most are LED’s which supposedly last a lifetime. Is this because they are so bright, perhaps overloading them? In any case, no-one seems to be enforcing the requirement for both to be lit all the time.

I have noticed that as well. I thought it was possibly because the surrounding brightness of the sunshine was making one of the lights imperceptible, or because the angle of my observation was good for one side of the vehicle but not so good for the other – I don’t know whether the LED day running lights are aligned in any way. Drivers have a responsibility to check their lights but, as this Conversation has shown, many don’t and of those who do a proportion do not rectify a fault. For many cars with day running lights a failure would be within the warranty period.

Beryl – Sorry, my comment was ambiguous. I was alone and ‘we’ referred to the drivers.

I have frequently drivers if they have a faulty light or an under-inflated tyre when I have followed them into a supermarket or other car park. If we were invited to report cars with faulty lights I would be happy to oblige, but it’s not something I have ever reported to the police. I have reported car numbers when I have witnessed incidents such as cars shunting others when parking. Many years ago I approached a driver who was putting a note on the windscreen after I witnessed him hit a neighbour’s Morris Minor in icy conditions. It turned out that the car had already been hit and another driver had left a note. I wonder how the insurance companies sorted out that.

Perhaps a website could be set up to allow us to report problems, location and time/date.

I wonder if the automatic number plate recognition system could also identify cars with faulty lights so the process is automated in the same way as speed cameras, so that we are not reliant on anyone reporting faulty lights.

I must say the “big brother” approach does not appeal to me. It can lead to vindictive reporting or, at least, a holier than thou approach. When someone will not know they have a faulty light it is surely sensible to try to inform them rather than report them to the police (who have better things to do given their austerity budgets, particularly in investigating things that happened 30 years ago. And I thought “New Tricks” was just fiction, with a small cast). Particularly when you cannot easily replace many lights without a trip to the garage.

However, helping when there has been a “bump” is something I support. Whilst I think we are (all) too precious about the slightest mark on our beloved cars – why not have rubber panels like some vans; ah, it’s style isn’t it – the villain who really damages your vehicle and disappears without trace needs dealing with. Particularly those who ensure they are seen leaving a note on the windscreen – with a false address or phone number.

There is also the possibility that the lamp had failed very recently. I once checked my lights in the MOT waiting area and when tested ten minutes later, the number plate light was not working. 🙁 The tester showed me the problem, and the lamp worked, but my next journey was to the dealer to buy a new lampholder.

Unfortunately a bump can cause hidden damage even if it is invisible. I do agree about rubber strips, preferable at a standard height. Unfortunately they don’t sell cars.

Hopefully Which? is looking at the problem of cars where an obligatory lamp cannot be changed without tools at the roadside. It is amazing that the motor industry has not tackled this irresponsible behaviour long ago.

I check my rear lights when I park up out side any shop.(after dark) The lights can be seen in the reflection in the shop windows. One vehicle needs a payment of at least £105 to change a side light bulb. How crazy is THAT?.

When I buy a car I check that I have spare bulbs for the exterior lights so that they can be replaced if needed. I recently realised that my stock did not include a spare for the daytime running lights and not that the car is approaching seven years old they might fail at any time. The local Halfords store stocks the bulbs (H5 715) at £22.40 each. I’m not sure what is special about them but hope it means that they last at least ten years because I won’t be buying spares if they are not needed.

As a good news story, a few days ago, working all by myself in my garage at home, I was able to easily replace a headlight bulb on my 2006 Nissan Note. The procedure was as described in my owners’ manual, except that I could not remove the electrical connector from the bulb, until I had sprayed some WD40 onto the back of the bulb. In particular, gaining access only required opening the car’s bonnet.

As a side note, over time, the plastic used in the manufacture of my car’s headlights tends to oxidise and discolour, forming a translucent browny-yellow surface on the plastic.

After getting an MoT warning about this, I discovered and used DIY headlamp restoration kits to remedy this condition. At least for me, their use was preferable to the expenditure of £100’s on replacement headlights.

I’ve long since mused over this discolouration. Never used to happen with glass – at least not with soda glass. There were some particular bad boys of the late nineties to mid noughties, Fords were worst of the lot. As you say, fortunately the solarisation is only surface deep and can be burnished away. It’s worth subsequently – within a few weeks – coating them with UV protector to mitigate the effect for a few years (this can be reapplied in Spring each year usefully).

Discolouration of headlamp plastic does seem to affect some models more than others. If the light output is sufficiently reduced the need to rectify the problem will be mentioned as an ‘advisory’ on an MOT test, as Derek mentioned. There are plenty of YouTube videos about sanding headlights to remove discolouration, followed by treatment with a polish that will restore the shiny surface.

My car spends most of its life shaded from sunlight, which may be why there is no discolouration apparent. If I see a problem with cars of a similar age I might treat the headlights with UV protection polish, as mentioned by Roger.

Phil says:
1 January 2020

My car failed it’s MoT because of cloudy headlights three years ago. Thought the restoration kit I bought was a bit of a rip off, the component parts could be bought cheaper individually and I’m told toothpaste works as well as anything else. You also end up with a car which is minty fresh.

You will find YouTube videos of people restoring plastic headlights with a variety of products including toothpaste – which is just a mild abrasive. It’s probably worth polishing the plastic every year or after treatment to maintain the clarity of the plastic once it has been sanded.

I managed to find some quite expensive restoration kits in Halfords and a much cheaper one close-by, at Proper Job. The kit I bought there was hardly any more expensive than toothpaste, but contained 2000 grit wet&dry paper, two grades of a white (aluminium oxide based?) polishing compound plus polishing cloths. For me, using the 2000 grit paper wet was the essential first stage of getting back to clear glass.

For those not wanting to get their own hands dirty, I also noted that some of my local tyre & exhaust shops also offer headlight restoration services.

As a friend found out, it was quite expensive to have her headlights restored by a local garage, but still much cheaper than new headlights plus the cost of fitting. It’s encouraging that it’s a DIY job. I presume that using rotary sanding disks will make the job easier.

Of course, if motor manufacturers reverted to designing new models with standard circumference round headlamps made with generic glass lenses, interchangeable between types of vehicle and with plug-in wiring, this problem would be largely overcome. The same can be said for much of life’s equipment and appliances and is another dimension of the sustainability agenda.

Headlight covers are generally polycarbonate with a scratch resistant coating. UV causes yellowing eventually in polycarbonate, both from daylight and Xenon bulbs. UV inhibitor in the material delays the process for many years, particularly as the pc temperature will not be high (even streetlights with polycarbonate covers last many years and are subject to much higher temperatures when lit, with much higher output lamps). I have not had to clean my headlights but would suggest being very careful with the coarseness of the abrasive material and the way it is applied as polycarbonate is a relatively soft plastic – a rotary sanding disc could spell disaster .

Derek mentioned using a fine abrasive and wet sanding, one of the advantages of which is that it provides cooling. Autoglym has a video showing the wet rotary sanding procedure.

Polycarbonate and acrylics are chemically reactive and it’s likely that wheel spray containing tar and chemicals will contribute to gradual staining.

After many years of trying to maintain “scratch-free” polycarbonate motorcycle helmet visors, I was, at first, reluctant to apply the wet sanding technique.

However, I also discovered that, for my case, polishing alone was insufficient to remove the yellow/brown surface layer.

I suspect that only some makes of headlight suffer these discolorations. For example, I never encountered any problems with my 1999 Toyota Yaris, which I retired when it was about 11 or 12 years – and 195,000 miles – old. So my Yaris reached a similar age to my Note without any apparent signs of this problem.

The worst affected car I can think of is a Toyota Yaris, probably dating from 2006. The plastic is not discoloured, just opaque – presumably as a result of UV exposure.

Thanks, interesting, as that Yaris was made the same year as my Note, but by a different brand. I must confess I do now sometimes look at other cars of about the same age as my Note, to look out for cars with pairs of cloudy headlights, or nice shiny ones or “one-eyed-jacks”, that have one of each.

Yes – at one time I paid a lot of attention to fading of red VW Golf and other cars. A few like mine had different degrees of fading of different panels.

Using a UV protective lacquer might be the best way to protect restored headlamps but I wonder if this could peel or crack with time.

If just the UV protecting film has degraded then this can be removed abrasively and a new coating applied. I believe decent coatings require UV source curing, something beyond diy. If the polycarbonate cover has yellowed then this will extend into the surface of the material and cannot simply be removed by polishing. The pc surface can also haze due to UV, and become damaged by, for example, car washes.

Discoloured and/or hazed headlights can substantially reduce their intensity and change the beam pattern by diffusion. As headlights are such an important safety feature I’d suggest that if degradation is significant the best solution would be to replace them – as you would with other safety dependent worn components. Alternatively you might find what you need in a visit to the breakers yard to recycle someone else’s headlights .

Hopefully if people take prompt action, either DIY or having the job done, they can deal with the problem and applying UV-resistant polish can reduce further deterioration. It would be interesting to know if polishing headlamps in the early stages of deterioration would be an effective solution.