70 stang,
As others have said, the likely chain of events are:
1> Condenser fan stops working because of the fuse blowing. The fuse blows because, a. the fuse is the incorrect size, b. the Fan is going bad and eventually blows the fuse, c. something else on the same circuit is drawing to much power.
2> Once the condenser fan blows the pressure in the system continues to rise until it causes the pressure relief valve to open. (This is expected behavior if the compressor continues to run without the condenser fan running and no over pressure switch in the system)
If the system was designed properly, you would have a trinary switch at the drier to turn off the compressor once the safe pressure is exceeded. Since the system is empty, now is the time to add the trinary switch. That way, next time the fuse blows, you will not loose any refrigerant.
Take care, Scott