[codejp3]

Initial guess based on limited info - it's a moving part of some sort, possibly a fan or something with a bearing as @2011.2017.odyssey mentioned. Possibly an HVAC door motor/actuator.

See if you can narrow it down. Does it go away if you don't use HVAC at all? Does it go away if you stop using other systems?

 

[codejp3]

Is it possible that the sound is less of a high-pitched metal-on-metal sound, and possibly something more like wind noise getting through somewhere, possibly speed based and/or wind direction/speed based? Like wind sneaking through somewhere and acting like a flute and playing a high-pitched note under just the right conditions.

It would account for the semi-randomness, the connection to 40Km/H, and the shifting source locations.

Passenger side seems to be the culprit. Possibly door seals, glass seals, the opening under the windshield wiper tray where the HVAC gets outside air as input, and so on....

Just a thought.