high pitched

So, with the weather cooling down I'm getting a high-pitched squeel when the heat runs (and appears to be when cool air runs too)...which I'm thinking is an HVAC fan bearing or something like that. My diagnosis was pretty rudimentary... Turn climate control to higher heat --> Whine Turn...

Hey all, We’ve recently started hearing a high pitched tone coming from the right rear of our truck (2011 gx460). It is coming from under the cover near the plug outlet. Assuming the inverter must be there & it is making the noise. Anyone ever have anything similar & if so what is the fix...