74 f100 ac compressor clutch wire location

[wyoranch]

Hey all, I have a 74 f100 I just bought from my grandpa. 360 v8, auto, 71k miles. Factory a/c. AC wasn't blowing too cold, still has r12 in it, I'm converting to 134. Found out the compressor is going bad. It looks like at some point the clutch on the compressor stopped engaging and instead of fixing it some "mechanic" had run the wire for the clutch directly to an ignition on hot wire. So it stays engaged whenever the key is on. I assume this helped ruin the compressor, it never cycles. Anyone have any idea where the wire should go to? I have a Haynes manual and can't find it in the wiring diagrams