How To Change A Number Plate Bulb

Although your number plate bulb doesn’t effect your driving, it can be fairly frustrating when they don’t work and cause the dreaded error upon the trip computer. Luckily, they are easy to replace and we show you exactly how.

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How To Change Number Plate Bulb
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Whether you want to upgrade your number plate bulbs to a LED bulb or simply want an OEM replacement, it’s a relatively easy swap. Although they aren’t going to effect your driving, they are a legal requirement for all vehicles on the road in the UK. The police and cameras need to be able to clearly see your registration plate.

In terms of the MOT, if one or more of the bulbs aren’t working, your car will fail its MOT (section 4.7.1).

Choosing The Bulb

The majority of number plate bulbs are “Festoon” bulbs, which are available in a variety of different types. From standard halogen bulbs to modern LED’s, they are available in a selection of sizes to suit your vehicle.

Although the size difference is minimal, the millimetres involved can make all the difference. Most sizes range as little as 31 mm to 38 mm but the sizes can be found in your handbook, forums or various online car checker tools.

What You Will Need

  • Screwdriver or drill
  • Your bulb of choice
  • Cloth/wipe

How To Change Number Plate Bulb

  1. Unscrew the holders with a screwdriver or drill.
  2. Pull the old bulbs out of the holder.
  3. Clean the inside of the holders of any dirt (optional).
  4. Place the new bulbs into the holder.
  5. Test the bulbs work before screwing back in.
  6. Screw the holders back in place.

Number Plate Bulb

Problems That May Arise

Although relatively straightforward, changing your number plate bulbs can cause some problems. The first issue may be access to the holders themselves as not all car manufacturers make the screws easily accessible. If you cannot see the screws, we strongly recommend reading the car’s manual or enthusiast forums for guidance.

Another issue that may arise are incompatible bulbs, which may be working but flicker or malfunction. However, one of the most frustrating of them all is an error message that appears on your car’s trip computer every time you turn lights on. The error on the dash is more than likely going to be caused by a faulty bulb but if not, you will need to use an OBD2 scanner to read the fault code.


Replacing your number plate bulbs really is that easy and whether you want a LED bulb to match your headlight bulbs or a basic OEM replacement, you can do so with ease. For the best results, we strongly recommend cleaning the holders whilst they are out in order to further improve the bulb’s light output.

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