Things You'll Need
Instructions
Turn off the Wii and unplug it from the power supply. Take out all of the cords and set the Wii down on a flat work surface so you don't lose or damage any parts or pieces.
Flip the Wii upside down and and remove the single silver-colored screw. Remove the battery tray from the console and set it aside. This ensures that no power can shock the electronic system.
Remove all screws from the case. Obvious screws hold the case together at the corners and along the back, but screws are also hidden beneath the rubber feet and under the white stickers. Set the removed screws aside.
Lay the Wii on its side and remove the cover. It should wiggle off fairly easily. Look for the broken fan and see how it's held in, and if it's still attached to the power cord. Remove the old fan and the power cord attaching it to the Wii.
Install the new fan. Put the case back onto the Wii and put all of the screws back in place, along with the battery tray and the rubber feet. Plug the Wii back in and run it to be sure that the fan is working. Touch the case to see how hot it feels, and listen for the sound of the exhaust fan to make sure it's functioning.