A/C blowing fuse

[Ben IV]

I decided to put a belt on and see what I'm working with on my factory a/c system. Set the controls to a/c and turned on the fan, the compressor kicked in and actually got a little cool air. But a few seconds later the fuse blew. Put in a new fuse and it blew immediately. I did a search but most everything is blower motor related but mine works fine till you switch it to a/c. I had a problem blowing the heater fuse when I bought the truck but it turned out to be the fan switch, replaced it with a nos switch and problem solved.

I've never messed with an air conditioning system before so I'm not sure where to start. If anyone has any suggestions or tips it would be greatly appreciated.