What you need-
One tri-wing screwdriver
One 3mm LED of you color choice
One soldering iron with solder
About 3 inchs or wire.
Step 1: Take your wiimote apart
WATCH OUT: watch it the front of the wiimote has clips that hold it in place nad if you pray the wrong way they will break off, causing trouble, what i do is pray the back up alittle bit then stick a butter knife in side and pull up.
Step 2: Get your LED and wiring ready and put it in place
Once you get your LED out along with your 3 or so inchs of wire out and soldered. Its time to put it in place. You might have to work with the length of wire so just take it slow and dont burn or kill someone or something.
Ok well lets solder the wire in place once you have your 3mm LED soldered at the other points.
Make sure you dont switch the points up or the led wont work and could die.