Quadcammer

Ok, so its not associated with the rear hvac unit.

I used a metal extension to listen to various engine/related parts.

The compressor definitely makes noise when you turn it on, but it wasn't the "omg the world is going to end whine or knock". It was a little harsh, but certainly not wild.

Then again, the noise isn't ridiculously loud either.

While it certainly seems to be compressor related, its strange that as soon as the blower shuts off, the noise shuts off.

This leads me back to the blower motor. I stuck my head under the passenger footwell while someone else revved the engine, and I heard absolutely nothing, not a sound.

Christ im confused now.

Quadcammer

Ok, I finally grew a brain.

I removed the engine drive belt, and the noise disappeared.

Henceforth, I have determined, through process of elimination, that it must be the compressor.