My 97 Silverado, 5.7, A/C clutch continually engages and disengages. Naturally when I move my selector from A/C or Defrost it stops doing it. I can hold the A/C relay and feel it switching high and low. My A/C has worked fine all summer and now this. Does this sound like a clutch OR a compressor? Thanks.

Optional Information: 1997 Chevrolet Silverado Vortec 5.7
Already Tried:
Checked wire connections. Swapped AC relay and swapped back. Can feel relay going hi/low.