'75 Duster w A/C keeps blowing #5 fuse.

My slant-6 '75 Duster has factory A/C. The A/C will blow cold for about 10 minutes then the #5 fuse blows and the power to the compressor clutch is cut. Everything else in the car works except the A/C clutch. I can run a jumper to the A/C clutch and it works fine. I have poured over the diagrams for a '75 Dart here:

http://www.mymopar.com/downloads/1975/75DartA.jpg
http://www.mymopar.com/downloads/1975/75DartB.jpg

but nothing lists the A/C circuit. From what I can trace if the #5 fuse blows I should lose a few lights, but I don't. The fuse is a 20-amp so I know there is some serious power going somewhere, but surely it shouldn't be going to just the A/C compressor clutch. I'm tempted to run a relay setup to isolate the power to the A/C clutch and see what happens (using a 20-amp fuse in the relay power circuit).

I have searched all over and can't find anything that diagrams out the A/C circuit. I am hoping someone here knows it a little better than I do.