How can I tell which fan under the hood is making a squeaky bearing noise?

What is your question?

I first noticed a new sound/noise from inside the passenger compartment this summer, not so much or often in the fall, but now hearing it again louder. I think it happens when the a/c or defroster is running. I've gotten out and opened the hood when I've heard the sound a couple times. It sure sounds like a bearing going bad, but I can't tell whether the sound is coming from the radiator fan or the a/c condenser fan.