Strange humming noise when AC Is on?

[Aero843]

Strange humming noise from engine bay when the ac is on, anyone have an idea what it is? I had timing belt and pump done about a month ago, and also my drivers side is just blowing cold air and passenger warm air, thanks in advance
https://youtube.com/shorts/LEHGNWD4w68?feature=share

 

[380bhpdaily]

It’s the fan you can hear. Everytime you turn it on it’ll engage that fan to help cool the condenser. Also you need to regas it if it’s hot on one vent as when the pressure is low it’ll only blow cold the drivers side.