It's gotta be the mast bearing grounded inside the column. I disconnected the wire coming from the mast bearing, from the wire that is connected to the Switch terminal on the horn relay. Put the negative battery cable back on and voila, no horn honking, or relay clicking, etc. When I remeasured the voltage at all three terminals, I now get 0.00 on the Load terminal, 6.5V on the Battery terminal, and 6.5V on the Switch terminal (which again, is disconnected now from the mast bearing wire in the steering column.)
