ASUS ROG GL552JX - backlit suddenly not working

[CW24]

first of all, sorry for my bad english
so my problem start when my motherboard is broken, so i went to asus service center and they replace a new motherboard for me,
before they replace a new motherboard, my backlit works just fine
but now whenever i press fn + f3 or f4 , nothing show up on screen (usually there's a brightness level panel) , fn works fine with screen brightness control or volume control. so only my backlit control is not working
when boot up, my backlit keyboard is not turned on like it used to before
i've update to the lastest ATKPACKAGE from asus website too.
please help

 

[Laptop_Nerd]

Hi,

Please do try these troubleshooting steps that may help.
- First is to uninstall/reinstall the keyboard driver.
- Go to Device Manager and uninstall the keyboard driver.
- Reboot the laptop and it should reinstall the driver automatically.
- After the reboot do install the ATK package again.
- Here's the link:http://dlcdnet.asus.com/pub/ASUS/nb/Apps_for_Win8.1/ATKPackage/ATKPackage_Win81_64_VER100037.zip?_ga=1.21476409.305422646.1455979617
- Once installed, reboot the laptop again and test it after the reboot.
- If it will still not work I would suggest taking it back again to the ASUS support center so they can check the ribbon cable that connects the keyboard to the motherboard.