No power to the compressor

[aaronb2500]

Hi Guys,
When I bought my '98 B2500, the guy told me the A/C didn't work, so I'm trying to figure out why. So far, I've determined that the compressor is not getting any power. I've checked the fuses (that I've been able to find) and they look good. I've checked power at the clutch both with the connector connected and loose - nothing.
Is there a relay or sensor switch that I can check as well? My Haynes manual is about useless on A/C problems.
Thanks.

 

[aaronb2500]

Update - I found the low pressure switch, jumped it, and the compressor came on. I added a can of r-134a and the outlet temps dropped 20 degrees. So, it appears the system works but has a leak.