MacBook Air 2012 - WiFi not detected!

Hi!
I have a really nasty and dusty Macbook Air mid 2012, which couldn't turn on. After a dust-off and cleaning it turned on again. I think the charging port was making a bad connection. I have cleaned the logic board too with IPA and a light brush.
I have Bluetooth, but not WiFi. The WiFi card is getting a little bit warm, but nothing crazy.

How can I figure out what the problem is? Any known voltages out there or something like that? Can the U1800 (pch) chip have anything to do with this? Could the Airport card be half-bad?

Thank you in advance!