I just replaced my previous 17" Inspirion with a new Model 5767 (17") and the backlit keyboard remains lit at all times, 24/7, even after the screen has gone dark. I keep the system running 24/7, never going into sleep mode as long as it's plugged in, the same as I have done for all laptops in the past.
The previous Inspiron 17 also has the backlit keyboard, and it works perfectly, going dark shortly after being idle.
I have gone to all the mentioned steps, including the Windows Mobility Center and resetting the idle time setting to all of the different options, but the keyboard remains lit at all times...
I should not have to resort to manually turning the backlight on and off as needed. and to do so requires I open the Windows Mobility Center, as the noted keyboard shortcuts appear to work ( <Fn>+<F10> )
Any Help Appreciated. I just spend a week doing a clean install of all my software and files to clean things up from older system to system transfers to eliminate things that were no longer needed and don't want to do that all over again if this system is faulty!!