apparently has been changed from a magneto to distributor setup. I'm in the process of trying to finish up with a new 4 wire harness, and found out via the defective light switch that the tractor was partially converted. (Light switch coil and resistor are toast). Not only that, but I was given a new-fangled replacement light switch that doesn't want to co-operate and turn the dang lights on. I've verified with a digital-multimeter that the light bulbs are good, and I tried to follow the original wires (which BTW, the insulation disintegrated in my hands upon touching them) with the meter while trying to install the new 4 wire harness. It'll be light soon, and maybe I can go have a look see at how everything is wired now so you can answer my question(s) better. And, the question(s) is/are: Why do I have one wire left over, and why do I not have lights? 
Anyone done a change-over like this, and could you give some hints as to where else I need to look? The tractor does run (sounds might purty too!), and I need to verify what I'm seeing is that the tractor is indeed charging as it is supposed to . The ammeter shows a slight negative pointer on the dial. Again, I'd have to go look at the tractor to see where it is pointing to.
Thanks in advance,
Rick
Hope this will show up. From what I've written down, here's what I have. I hope I've described it well enough so anyone can understand. BTW, the wiring harness actually ahd 5 wires. One green, one brown, one gray (not currently connected to anything) and two different black wires that I'm sure go to the headlights. One of the black wires splits into two wires for the right and left headlights.
