EDIT: there's really no way to fix the problem of keeping the keyboard always on. The BIOS has an option for the backlit which doesn't allow for always on, but only temporarily. Instead, you can get the Feature Enhancement Pack from Dell (google for it) and that will add tabs to your Control Center Keyboard for lighting in Windows 7 (might be better in Windows 8, supposedly doesn't work for Windows 10). The tab only allows for up to five minutes on. But if you swipe your touchpad you can turn it back on again. The FN keys still work.
It's FN plus the right arrow. Here's an article on it and the other FN keys: https://www.cs.bham.ac.uk/~axs/laptop/d ... -keys.html
. I just spent an hour looking for the instructions, and as usual the internet informaion is wrong and the manual information is absent or not easily found, hence this link.
It should be true for all Latitudes, and might be true for other keyboards.
You hold down the FN key and then the FIRST strike of the right arrow key, turns the backlight off.
SECOND strick of the right arrow key, turns it on only if the ambient light is low, but only for so long as you're typing. About 60 seconds after you stop, the light turns off (very annoying, frankly).
THIRD strike of the right arrow key, turns it on permanently. Far preferable.
Well, you might have to reboot to get it to stay permanent. I'm not getting permanent, but only on/off.
Dell's own explanation is here: http://www.dell.com/support/article/us/ ... N285209/EN