Keyboard lighting stops in the dark

Question

when ambient light dims to total darkness, my keyboard light turns off. Do you know why? It seems to work in find in mild light, but as soon as all the lights go out, so does the keyboard. Frustrating for working in the dark. My screen does fine. Any thoughts or guidance appreciated.

Answer 1

Here is the full blog post (in case it goes away):
*Macbook Air has 3 Level of Ambient Light Detection?*
Here's a simple test. Lets label these levels 1 - 3 for simplicity where
Level 1 is the brightest ambient light, screen brightness is set to "max" and keyboard backlight is off.
Level 2 is the darkness level that you notice your screen backlight darkens for the first time. Keyboard backlight is on (as in you can set the brightness)
Level 3 is the next level darker than level 2. I observed that the screen darkens further and keyboard backlight is also on (brightness is setable).
To ascertain that we do have a third level, test out your MBA in a bright environment. Cast a slight shadow over the light sensor (left of the iSight) until the screen darkens for the first time. Next, completely cover the light sensor. You will notice that the screen darkens again.
Here's the funny thing. If the keyboard brightness for level 2 is set to anything but the maximum, the keyboard brightness will completely turn off at level 3. Conversely, if you turn the keyboard brightness on at level 3 (anything brighter than no light), the brightness will be set to max at level 2. If the brightness is set to max at level 2, it is reduced greatly at level 3 probably to be less distracting.
Several Macbook Air users have complained about their keyboard backlight not working as advertised -- they have the backlight come on in semi-dark, then turn off again. The above observation seems to fit their situation quite well so if you are one of them, just cover your light sensor, set the brightness and see if that works out for you.