This is a Known issue with MacBook Air and Pros in Mid 2011-2012 due to a trackpad and keyboard input device update here is what you should try.
------------You need a functional keyboard to make this work-----------
1 Press Control-Fn-F7 (this enables all commands via the keyboard).
2 If the Updater application is on the screen, go to step 7. If the Updater application is not on the screen, continue to step 3.
3 Press Command-Tab to go to the Finder.
4 Press Command-Shift-U to open the the Utilities folder.
5 Use the arrow keys to navigate to "MacBook Trackpad Update" so it is highlighted.
6 Press Command-O to start the application.
7 The word "Update" should be highlighted in blue. If it is not, press the Tab key to highlight it.
8 Press the space bar to initiate the update.
9 Press Return to confirm OK.
10 Enter your administrator password, then press return.
11 Allow the update to finish. Do not unplug the computer, let it sleep, or interrupt the update while it is in progress.
12 The word "Updated" with a green checkmark appears in the progress box when the update is complete. The trackpad should now be functional
crwdns2934105:0crwdne2934105:0
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crwdns2947414:01crwdne2947414:0
Good morning, I know it's been a long time since the post but I'm currently having the same problem, keyboard and mouse work on one board and not on another, were you able to solve it?
Thank you very much in advance
crwdns2934271:0crwdnd2934271:0 Luiz Lopes crwdne2934271:0