Air conditioner?

Hey Bob and Ken,
Great informative site. I have a '99 Chrysler 300M with 86k miles. A few weeks ago I started to notice a noise that I've not heard before when the air conditioner was engaged (kind of sounded like a diesel truck), and figured that the a/c was just straining due to the above 100 deg temp we're having in Dallas. Last night I was driving with the same noise starting then noticed the air was starting to feel a little warmer until the a/c clutch just stopped turning all together. I brought the car in to a local oil change station and had the system checked. The tech told me that I would probably need to have the system replaced after he verified that the refigerant level was good, the dash switch controls were good, relays and fuses were all good, and bypassing the cable to the system by probing them from the battery witch got the clutch to kick in but the system did make a lot of noise. Then just to check and see what it would do he turned it off at the dash then back on, the clutch didn't kick in by itself.
I would appreciate any advice you may have.
Thank you,
Rick