Wiring a R-4 A/C compressor

[sgaylord]

I put a serpentine system off a 89 Chevy truck on my 69 CST-10. I am having difficulty trying to figure out how to wire the compressor. My 69 has factory air with only 1 green wire for the old A-6 compressor but the R-4 has 3 wires. 1 green (I assume this is where I would connect the green wire that previously connected to the old a-6 compressor), 1 black (I assume this is ground) green and black are connected on the front of the compressor, and 1 tan on the rear of the compressor (I have no idea where this one (tan)connects) . I know others have installed these before but I could not find anything in my searches for r-4 a/c compressor wiring, r-4 compressor wiring, etc. Can someone help me figure out how to wire this thing? I have included some pictures to show what I am talking about.