Mac Book Air 13 2010 does not fall asleep when closed - what could be?

Question

macOS

I have a Mac Book Air 13 from 2010, it was originally running OSX El Capitan, installed High Sierra - I don't know if that matters.
Now, when the lid is closed, it does not fall asleep - is it a physical malfunction or something software?

Answer 1

I don’t know how it is on your model, but on the old ones (2010) there were magnets that switched the laptop to sleep, did you / someone disassemble the laptop and lost it? (if they exist at all now)
Also, a sensor was built into the connectors who understood that you closed the lid (the same magnet) mb it broke ...