Keyboard Backlight

I'm not sure what the problem is, but it seems not even an OS reinstall helps.

I have and intermittent problem where I can't turn on the keyboard backlight. I hit fn-F6 and the little display comes up but there is a circle with a line through it. If I leave it alone for a little while, the backlight will come on by itself, stay on for a little bit, then go out and I won't be able to turn it on again.

Any suggestions on a) things to check or b) something to do to fix this??

Thanks

If the light sensor detects enough light you wont be able to adjust it. Have you tried it in a dark room. The other option is Lab Tick which allows you to have it on all the time and what brightness or always off.
http://labtick.proculo.de/

That would explain why it seems to "intermittently" work. I even called Apple and they had no idea short of reinstalling OSX.

Thank you!!!

Edit: I think you should apply for a job at Apple!!! Thank you again!