worrysome noise?

Alright, I have just completed the u-joint in the front driverside axle and after starting the jeep to take it out for a test run we immediately heard a new noise coming from the engine bay. This noise seems to be grinding and whining and I know this sounds weird but thats the best I can describe it. We believe this noise is coming from the AC unit but not entirely positive. Any suggestions?

A/C clutch bearing? Turn your A/C on, does the noise go away? If so, it's the bearing. Mine's doing that right now, I'm replacing the bearing. It makes a loud whirring/whining noise/grinding noise.