macbook air - screen is dark, the light switch on keyboard functional but doesn't change the brightness
My main macbook air screen turned dark all the sudden. I can see the brightness button is functional as I see the dot moves when I press it on the keyboard but the actual brightness of the screen does not change. I am making it work by connecting it to a monitor but how do I fix the brightness of my main screen? Thanks in advance.
MacBook Air 13″, OS X 10.11