Question Asus GA502DU Keyboard backlight not turning on

[NovaExt]

My keyboard backlight won't turn on. All the keys and special functions work. The brightness keys for the keyboard display on the screen that the brightness is being changed, but the keyboard backlight doesn't respond. The caps lock key still shows the activation light too, so I think its a software issue but I don't know. All the software is in place and so are the drivers.
Help pls

 

[Fix_that_Glitch]

Have you tried the Fn+f4 key to increase lighting? Did you recently install something new?

 

[NovaExt]

Have you tried the Fn+f4 key to increase lighting? Did you recently install something new?

Already try to turn on the backlit fn+up but nothing happened. I installed some update from the settings>update