How to disassemble a Wiimote.
Source: SICKmods : Wii > Disassemble*Wiimote
Recommendation: Make sure you dissipate any static electricity you may have built up as it can cause damage to the circuit board!
Finding your wiimote:
It looks like this.
Removing the battery cover:
A simple clip keeps the cover on.
Taking the batteries out:
Just like you would any other battery operated device, the batteries just come right out. It'll look like this when the batteries are out.
Taking out the screws:
Grab your tri-wing screwdriver and take out the 4 screws indicated in the following picture.
Taking the top half off:
This part may seem difficult. There are 2 clips in the front of the wiimote that hold the 2 halves together. You may want to take your flathead screwdriver and use it to assist you. But just keep prying and wiggling. It'll give eventually. Try not to break the clips or else you're gonna need to glue your wiimote back together. The following pictures will show you where the clips are located and what they look like.
It'll look like this once you get the top half off.
Removing the PCB:
The wiimote internals/PCB just come/s right out. I recommend pulling up from the back. It'll look like this once you get it out.
Removing the B button and the IR cover:
The B button comes right out. I recommend pushing from the bottom of the button. The IR cover also comes sliding right out. Just grab it and pull up.
Taking the plastic thing off the PCB:
You'll notice a little circular object with 2 wires (red and blue) laying in a white plastic device. That would be the rumble motor. It pulls right out and the wires come out from their little clip. Then the white plastic thing comes right off the PCB. There are clips on both sides. Just unclip one of them and bam. It's off.
And that's it! Completely disassembled!
For powering LEDs (for your A button, B button, or Power Button), use these 2 points.
For replacing the player indicator lights (SMDs). They're located here.
Full creidts for this guide go to the guys at SICKmods.net