The keyboard backlight is not working

Hello everyone!

I bought a used MacBook Pro 16 (2019), and it needed cleaning. I removed kilograms of dust, put everything back in place (everything is now in perfect order), and just today, while watching a movie in a dark room, lying in bed, I discovered that the backlight isn't working. I usually use the laptop connected to an external display, so I didn't notice it immediately. Plus, I don't remember when I bought it whether I checked if the backlight was working.

Please help me figure this out. Does the keyboard backlight have its separate cable? How is it connected to the motherboard? If anyone has photos of this board and an example of how the power and control for the backlight are organized, I'd appreciate getting those photos. Could I have simply forgotten to reconnect a cable during the MacBook's reassembly?

Thank you, everyone!