Screen is black won’t turn on

hi, this may be an NVRAM problem

1,Turn off your macbook Air and unplug the AC

2,Hold down Shift + Control + Option and the TouchID button for 10-15 seconds.

3,After this time, release all the buttons at once and reconnect the AC

4,Turn on your MAC

OK ... next

Another option is connect your Macbook to an external monitor - you have this option ?

Anyway for service :(