Picture of Festoon Bulb Adapter
In this instructable, I will show you how I made an adapter to allow me to upgrade my Toyota Corolla interior dome light. The smallest festoon LED i could find (on the high-street) was 36mm however my Toyota's festoon bulb was only 31mm. I thought it would jam in but unfortunately it was just too tight. 

Remove these adsRemove these ads by Signing Up

Step 1: Tools & Materials

Picture of Tools & Materials

UK Plug with serviceable fuse
Old AC power cable (or an old HB pencil)
Previous festoon bulb (or tin foil)
Insulation tape


Soldering Iron
Stanley Blade
Wire Strippers
Soldering work clamp (or in my case a pair of mole grips)

Step 2: Dismantle Plug

Picture of Dismantle Plug
I have a lot of redundant UK plugs in my house as I have moved to New Zealand and so had to replace the plug on a lot of my appliances. If you don't have a UK plug you could buy a fuse holder from jaycar.

You need to open up your plug and remove the fuse holder clasps. One will have a leg attached the other a wire clamp, we'll get rid of these with the Dremel cutting saw.

Step 3: Build Spacer

Picture of Build Spacer
The spacer is going to be the bit that sits in place of the incandescent bulb.

I used a section of insulated power cable, but you could use a all piece of pencil. Cut it slightly shorter than the full length of the old bulb. I then wrapped the ends with insulation tape to make sure the core wires couldn't make any electrical contact.

I then removed the contact caps from the old bulb and simply pushed them on to each end of the spacer, you could use a crimper to make them more secure but be careful not to warp them too much.