From the looks of the harness, I'd say that when the PTO engaged, it was killing the voltage level from the switch to the coil due to poor connections. A new wiring harness, or you could just put individual spade connectors on, and a new switch, and you should be good to go.
I said my prayers today at mass, let the good lord shine down upon my tractor and I. I just tested continuity, and the ignition is complete junk. Update coming tomorrow. Thanks Howard!
Edited by pvk, July 21, 2013 - 09:07 PM.