Pulley Chirp

So, i just picked up a 1997 4.6 GT from the 2nd owner. It has been babied and very well taken care of. Guy said that AC blew cold. When I went to pick it up, he said that in the last 5 days it developed an intermittent chirp from what sounds like the tensioner pulley. The AC compressor is also not working properly as evidenced by it not getting cold. The fans blow, then freon is full (according to the gauge on the artic ice ac recharge bottle). Is it possible that the chirp I am hearing from time to time is the ac compressor, or would it more likely be from the tension pulley? Like I said, it has only recently started, is not constant, and all other belt driven accessories are working as they should. The fella was very adamant that the AC has been blowing cold as he was using the car as a daily driver up until about a month ago when he bought a small truck. Aside from this, the car is in AMAZING shape. I'm not running the AC in fear that I will mess it up or cause extra load on the belt and tensioner. I don't want to screw up this engine as it is currently running like a sewing machine. It is hot as hell here in South Georgia (110* today) and I NEED AC! Help......

So, putting the AC compressor to the side, could the "chirp" I'm hearing be coming from the tensioner or idle pulley? Also, if it is a pulley chirping, or ac compressor, is it okay to drive??

I understand the concept of the stethoscope, but, I do not feel competent enough in my mechanical knowledge to diagnose it myself. Now, a human body....sure. I just want to know that my driving it to and from work isn't going to f*ck it up.

it was the tensioner. Went ahead and replaced idle pulley as well and a new belt. Also new AC compressor, orifice tube, and dryer. She is now running like a champ and freezing my nads off! This South Georgia heat don't play! It was 110* today and is supposed to be hotter than that tomorrow!