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The questions and answers in this section of relate to previous versions of the MOT manual and should not be relied on, as the law may have changed. Please ensure you check the relevant section of the current MOT manual, which can be found on this site.

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Daytime Running Lights

Q I am installing daytime runners on my car. Do they have to turn off completely when the headlights are turned on or can they be dimmed Most of the controllers I can find just dim them.

Name: Mark Wright

Dedicated daytime running lights

Daytime running lights DRL are purpose-made, low-wattage lights that can be fitted to a vehicle and used during the day to improve the visibility of a vehicle to other drivers as well as pedestrians, cyclists and other road users. They do not need to be operated manually as they automatically activate when the engine is started and turn off when the engine stops or when headlights are switched on at night.

DRL are necessarily bright to ensure they are visible in the daytime but not so bright that they will dazzle others. However they are too bright for night time use and are not intended to illuminate the road in the dark. If used at night they will cause dazzle and discomfort to others and so drivers should always switch to their position lamps or headlamps at night.


Research has shown that DRLs are likely to reduce multiple vehicle daytime accidents and fatalities by up to 6 once all vehicles are equipped. DRL are likely to result in a small increase in fuel consumption and CO emissions of around 0.5 but this is expected to be lower when LEDs are used in place of filament light sources.

Legislation and requirements:

Vehicle manufacturers must fit DRL to new types of passenger car and light goods vehicle car derived vans type approved to European vehicle requirements from February 20111 . In practice this means that any new model launched after this date, and many launched before, will be fitted with DRL. However, existing models on sale before this date without DRL fitted can continue to be sold and used indefinitely.

Similar requirements apply to large vehicles such as HGVs and buses from 7 August 2012. Motorcycles do not currently require DRL to be fitted, but most manufacturers voluntarily opt for an AHO Automatic Headlight On system to be installed as an alternative. Changes to European legislation will, in future permit manufacturers to fit DRL on their motorcycles.

DRL activate automatically when the engine is started and remain on unless the headlamps are switched on. They may however remain off in some low speed and stationary situations. In general all other lights should remain off when the DRL are on but for a limited period some vehicles may be available which automatically activate the rear position lamps at the same time as the DRL.

DRL may be combined with other lamps. For example some manufacturers use the same lamp for both the DRL and position lamp. In these cases the DRL automatically dims to function as a lower intensity position lamp when the headlamps are turned on. DRL placed close to direction indicators may also automatically dim when the direction indicator is active. This is to ensure that the direction indicator is not masked by the light from the DRL.

Retro-fitting DRL

There is no requirement to retro-fit DRL on vehicles not fitted with them as standard. If you decide to retro-fit DRL you should ensure they have been approved to the correct European legislation. This can be confirmed by checking that the approval mark embossed on the lamp contains the letters "RL", see figure 1.

Ideally retro-fitted DRL should be installed such that they activate automatically when the engine starts and switch off when headlamps are turned on. If this is not the case then you must ensure that you manually turn DRL off at night as they will cause dazzle and discomfort to others if used in low ambient lighting conditions.

DRL approval mark.

Use of other lamps during the daytime

Drivers of vehicles that are not fitted with DRL are not required to turn on their headlamps or position lamps during the day unless visibility is very poor. However some European member states do require some form of lighting during the day so if you travel abroad and do not have DRL fitted you may be obliged to drive with your headlamps on.

Running lights

Q would a car fail the mot if running lights are not workn

Name: johnny

Running lights are not part of the MOT unless they are part of your side lights/headlamps configuration

Add more daytime running lights

Q Can I have more than two daytime running lights on my motorhome

Name: Mike

Daytime running lights are not tested as part of the MOT test unless they are part of the normal headlamp display. Extra ones are not tested at all.

Daytime running lights

Q Hello, I have a 2010 Citroen C5 due for an MOT. One of the daytime running lights has blown, will the cause a MOT failure

Name: JohnH   Town: Kidderminster

Daytime running lights are not part of the Test

Side running lights

Q Are working LED side running lights required for MOT on a horse lorry 7.5 not HGV

Name: Michelle Barnard

Yes. If it has got an area for carrying motorbikes or cart or even race cars, horses or such like it should be tested as a goods vehicle. These lamps are then testable.

Backup brake lights

Q Mercedes MLs have a habit of the backup brake lights being used when the connection to the normal brake light has failed. The fog lamps are used as brake lights when this happens. Would this be a UK MOT failure when tested

Name: martin

As long as you have high intensity red lights that light up when the brake pedal is depressed and extinguish when released and they do not affect the normal light I.e. side/running lights

Amber side running lights

Q I have a motorhome with 4 amber side running lights on each side. A couple of them are not working is this a fail

Name: G howe   Town: Bognor Regis

Side marker lights are not required on motorhomes, Optional lights are not testable on a class 4 test. These lamps are not normally fitted unless the vehicle is a living van rather than a Motorhome. A living van is a vehicle constructed with living accommodation but also has a load carrying area. If it has got an area for carrying motorbikes or cart or even race cars, horses or such like it should be tested as a goods vehicle. These lamps are then testable.

daytime lights

Q Do daytime lights need to work for the car to pass an MOT test

Name: Alan Humphries   Town: Inverness

Daytime running lights are not tested as part of the MOT test. However the lights must function normally at night if they are part of your headlights/side lights.

Tail light out

Q can you still drive lgv with one of the rear tail running lights out

Name: Lewis   Town: Muirhead

You cannot drive any vehicle legally with a tail light out

American Motorcycle lights

Q I have an US imported motorcycle on which the headlight and tailight are always on and there is no switch to turn them off, only a low and main beam. Also there is no side light fitted nor a switch for one. Will this pass

Name: John   Town: Bideford

Daytime running lights are not part of the test

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Daytime running lights

Q My daytime running lights are being changed to fog lights with a switch to turn off during clear weather is this legal

Name: Margaret grantham   Town: bradford

DRLs are designed to make vehicles more visible during daylight hours and are now common on vehicles of testable age. DRLs themselves are not covered by the manual and are therefore not testable items.

Daytime Running Lights

Q Does a daytime driving light fail an mot if it is not working

Name: Jay jay   Town: Liverpool

Daytime running lamps are not testable unless they replace the front position lamps. Where this is the case, they should dim when the position lamps are switched on and may extinguish when the headlamps are switched on.

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