Macbook keyboard backlight doesn't work The keyboard of my Macbook Pro mid-2010 has stopped illuminating in low light.

I checked my System Preferences of my Mountain Lion and there is no "Automatically illuminate keyboard in low light" at all. Also F5 and F6 don't work either while F3 or something like that works perfectly. 

I googled this question, and everywhere writes that there is a special point in system pref, which i dont have. screen Any suggestions on how to identify/fix the problem are greatly appreciated
For all kind of hardware-related issues, I will recommend that following,

Reset your SMC, NVRAM. You can find guides for SMC here, NVRAM here.

If that doesn't help, boot into Safe Mode, you can the guide here.

The last step, is of course, to Time Machine it and reinstall the OS. Reinstall, not upgrade.

The very last thing is Genius, or repair it.

Update: some other fixes

I forgot the following things to do before giving up.

a) Create a new user account and see if it works

b) Clear your cache with things like CleanMyMac or other free alternatives.