Chosen Solution

For some reason my macbook keyboard and trackpad are completely non-responsive. I know for a fact that the keyboard and trackpad are not the problem. Please don’t fixate on replacing the keyboard and trackpad. I’ve tried replacing them multiple times with the same results. Here are some other things I have tried:

  1. External keyboard and mouse work perfectly fine. I can log into OS X and everything functions normally with an external keyboard and mouse.
  2. I performed an SMC reset using the built in keyboard. As I said, I know the keyboard is good.
  3. I can not reset the PRAM using the built in keyboard. I can reset the PRAM with the external keyboard. The keyboard works before the chime (SMC reset) and does not work after the chime (can not reset PRAM). It seems like the logic board is turning off the keyboard when it chimes. Not sure what could cause this. Does anyone have any ideas?

Both the internal keyboard & trackpad are connected into the same controller chip the external USB ports do. In fact they are USB devices! So we need to look at this from a software side first. OK, Can you run AHT on your system using the wired keyboard & mouse? Follow this Apple TN: Using Apple Hardware Test. See if it tells us any errors. The next thing I would try is starting up the system in safe mode. Follw this Apple TN: OS X - What is Safe Boot, Safe Mode?. Let us know what you discover.