Ford Windstar

I have a 1998 ford windstar w/156000 miles on it. It has a 3.8lt v6. My question is I just put a new serpentine belt in my van and noticed that the compressor is not turning like everthing else. Does this mean my compressors no good or is that what it supposed to do when the ac isn't on?
Bob w 1967
June 12, 2007.

So if the pullet's not turning than I have a problem?

Bob w 1967
Jun 12, 2007.