Backlit keyboard inspiron 15R SE 7520

Hi Umair,

Welcome to Dell community!

Do the other FN key combinations such as FN+F12 to increase the volume work? Also, when you open “Windows Mobility Center” does it say “Customized by Dell Inc.” within the window?

Let us try reinstalling "Dell Quickset" which can help us with the issue:

1. Press Windows key and the “X” key together for the “Power User Menu”
2. Click “Programs and Features”
3. Right click “Dell Quickset” and click “Uninstall”
4. Follow the on-screen instructions to complete the uninstallation and restart the computer
5. Refer the following link to download and reinstall Dell Quickset application: http://dell.to/12ZDvvV
6. Restart the computer once the installation completes
7. Try using the FN+F6 key combination and check if the keyboard backlight works
8. If the issue persists, press Windows key and the “X” key together for the “Power User Menu”
9. Click “File Explorer”
10. Browse to “C:\Program Files\Dell\Quickset”
11. Double click “BacklitKB”
12. Ensure that the “Keyboard lighting” is set to “On”

Do let me know the results.