While messing around with an older Nintendo Wii remote (without Motion Plus) I found the following pinout for all the buttons on the controller. The vias lie right where the speaker sits, underneath the Broadcom chip. Pin 13 ("Common") is the common line that all the buttons connect to. You can use ground instead, but I thought I'd still include it in the pin-out. Zoomed out view of the front of the Wii remote circuit board. I also found that you can remove this chip and the controller will still function normally (I haven't tested it extensively). I believe it controls the speaker, so removing it may conserve power.