17 R4, backlight does not work

Service Tag:

Good evening,

The keyboard backlight does not work. I tried everything I could and found it on the Internet on this topic. But I noticed the regularity: when I turn off the laptop (press shutdown) and unplug the power cord for a day or more. After this time I turn it on without connecting the power cable, everything works! If I just close the lid and put the laptop into sleep mode for a short time (up to 2-3 hours), then opening it all works. But if it lasts longer (more than 3 hours) I open the backlight does not work. If you go to the Alienware Command Center, we’ll find this message: The device you have selected is included in the current theme, but AlienFX cannot detect this device in the system. Do you want to remove this device from the current topic?

Please tell me what to do with it, do I need to carry a laptop to the service? So, as I work in the dark, the backlight is very necessary, and it is not convenient to disconnect the cable all the time and go to the end of work. Maybe there is some solution to this problem?

Thanks in advance, Vladimir