Fitting LED bulbs to your car


One of my favourite modifications to a car is also one of the easiest – getting rid of those yellow, dated looking incandescent bulbs and fitting LED replacements.

There’s a number of lights around your typical vehicle which can benefit from being replaced with LED bulbs, and changing them is not as difficult as you might imagine.

Here’s a few you might want to consider looking at:

  • Interior dome light bulb(s) including map lights and vanity mirror (behind the sun visor) lights.
  • Interior door entry or foot well lighting.
  • Boot space lights.
  • Rear license plate bulbs.
  • Rear brake lights and indicators.
  • Front parking lights and fog lights.
  • Side indicator bulbs – special requirements are needed here.


What to do first


Firstly, you must ascertain what bulb types your vehicle uses. For interior lights, this is usually as simple as prying off the clear plastic light covers and pulling the bulb out – close the doors or turn the lights off first so you don’t burn yourself! You’ll then need to inspect the bulb to work out what type they are. They’ll either be a wedge style bulb that simply pushes in, such as a T10, or they’ll be a longer style bulb known as a ‘festoon’ which has connectors at each end. Write down the code types as you’ll need to refer to them later.

For exterior lights the process varies. License place lights can typically be accessed by prying off the clear plastic covers and then pulling the bulb out. Rear brake lights and indicators are often accessed via panels within the boot area, while head light or front parking light bulbs are accessed from within the engine bay, with connectors visible along the rear face of the headlight housing. Some vehicles may have limited access here, so be sure to consult your car’s handbook.


Finding LED replacements


After jumping on eBay and searching ‘T10 LED’ for example, you’ll find a multitude of different options. The T10 actually has the widest range of LED options available, and you’ll notice I’ve shown 4 different examples in the photo above. Your best bet is look for reputable sellers who have sold larger quantities and also bearing in mind that generally the more LED’s there are on the fitting, the brighter it will be.

You also need to take note of how your existing bulbs look (size wise) and also what space is available in the housing, as some more powerful LED bulbs might be too big or too long to fit. Using the T10 LED bulbs shown above, I’ve found styles 1, 2 & 4 to fit in all situations I’ve ever used them, while finding uses for style 3 is difficult as the bulb is often too long to fit.


Replacing your existing bulbs


The process of replacing your existing bulbs is basically the same as when you inspected them, except you’re obviously slotting the new bulb in.

An important thing to remember with LED bulbs is their polarity – which basically means they only allow current to flow in one direction. For you, this means that the bulb will only work if it has been plugged in the right way – so if it doesn’t illuminate after you fit it, simply pull it out, spin it around the opposite way and re-fit it.


Notes regarding LED head lights and fog lights


Whilst browsing eBay I’m sure you’ll notice sellers advertising LED head light and fog lights. Whilst you can probably replace your fog light bulbs with LED’s relatively safely, I certainly wouldn’t recommend doing the same with your headlights. The simplified explanation for this is while LED’s look brighter and offer a more pure looking light, the way the light is generated usually means they don’t penetrate the darkness anywhere near as far as your vehicle’s original incandescent light bulbs would. Safety is critical and you definitely need to be able to see when you’re driving at night, so don’t do it!

Replacing your fog light bulbs with LED’s is a safer proposition, as they generally come with lower wattage bulbs anyway and they’re less critical to the operation of the vehicle. But it’s important to note that the light pattern of an LED bulb will differ from your vehicle’s original incandescent bulb, meaning the way the light shines out on the road ahead of the vehicle will look different – often more scattered looking and not quite as bright.


Important note regarding indicator bulbs


Replacing your indicator bulbs is much the same process as any other light on your vehicle, but with one important difference. You car’s indicator wiring circuit has been set up for light incandescent light bulbs with a particular amount of resistance. In comparison, LED lights offer little electrical resistance – and for you this means your car’s indicators may “hyper flash” (flash very quickly) if you replace all the bulbs with LED’s.

In order to fix this, you must either purchase LED bulbs which are advertised as being indicator bulbs and have resistors built in, or you’ll need to purchase separate resistor units which must be spliced into the wiring circuit to slow the flashing back down to the normal speed. This is obviously a more involved process, so if you aren’t confident with the job I certainly wouldn’t tackle it yourself without doing some research first and having the necessary tools.