Easier to tell you...
Remove cabin air filter and leave housing open. Open up all vents and turn fan on high. Windows all open too.
While it's blowing, you blow into the vents from the engine side...trying to kick off whatever dust might have accumulated and be 'off balancing' blower fan. I changed vent positions, varied the speed of the fan while blowing from the other side. I had my cricket sound starting. This stopped it.
I used a wet/dry vac as blower, but compressed air would work too...just easy on the pressure with compressed air, as you don't want to blow anything apart!
Anyway, I did this about a year ago, and so, for me, this worked. Hope it does for you too...but I still think it might be the fan sucking air in so it knows the cabin air temp...the tiny louvers in climate control...1/2" diameter circle with tiny louvers. Search on that. Also search chirping or cricket noise...bet there are many threads on that...some might have other sources/solutions for you.