Coil: If old coil works, no problem. I just remember seeing a worn out tired coil in some pic.
Harness usage: The answer I've tried to relay is that the few wires we are doing right now and in my post above may not be part of your harness. I can't deal with the colors and the questions regarding your harness as it relates to the few ignition wires. Just as long as you have wires hooked up the way I describe for start/run, it does not matter if you want to call it a harness or use your harness or use some wires off a spool. I can not answer questions about your harness or what wires are already hooked up. So I decided to approach it in a simple way. Simple steps. Most of your harness is for lights, accessories, gauges, horn, turn sigs and so on. After you get these few wires hooked up per above, we WILL use your harness for the rest of the truck. A harness is 99% wires coming out of a fuse box and going all over. The wires above, in my post, DO NOT, therefore I DO NOT consider them part of the harness. As I've said, forget the harness for now. If there are wires that you see that can be used from the harness, use them.
What harness brand and Part No. did you buy?
Harnesses are broken up into branches and there are several smaller harnesses within a kit sometimes. If you want, we can call these wires "ignition harness." As said earlier, your harness may be built for a stock truck, your ignition and your charging system are not stock and therefore some auxiliary wiring needs to be done. That's what we are doing now.
As you can see, the confusion you have is caused by you not understanding the harness that you bought and PO wiring. You say you bought it to do your own wiring. That is what you are doing with the start/run part. Move forward please.
