A couple observations...If you mean a wire from the hot side of the battery to EITHER connector on the key switch that would be a BIG mistake. All the key switch does is supply a ground to the EHC.
Think wire in/wire out. If there is a hot wire from the battery to the switch, think of that prong as not touching ground or passing current thur the switch. It's as if the switch is not there, the wire is dangling in the air, you are going to alligator clip to that post all hanging in the air [you have to think] not grounded at all, correct?
If you supply power to one side of the coil while the other has got a ground the coil could very likey overheat...
How is this box hooked up? Wire in and wire out, right? I don't care how many wires, is there a ground and a hot wire? So, does a hot wire go to the coil from the box?
Coil wise, you can't see the wires inside, but it still says, [1] wire went in/[1] wire came out. If I run a hot wire to one side of the coil, it is going to fire first. If I have a problem with the mounting of the coil and flipping it around is the better fit, where are my forward and rear coil wires? On the opposite side. Why? Because the coil does not care what side you fire first, right?
It's all about wire in/wire out. One is hot going in, one is ground coming out. What is the difference I put the ground as the key and it goes to hot? Do I still need 12v to the box? Does the toggle switch care what side you put the wires on? It either sends the hot down the wire or you flip the wires on the switch, and the ground is now the wire out to said next junction = To complete a circuit.
Say I have 7 wires out the box:
1. Right wire signal to cone cover or the advancer plate.
2. Left wire signal to the cone's advancer plate.
3. Ground to advancer plate i.e., the hall effect where the cup has the two cut windows it needs to pass thru to fire R/L cylinders, right?
4. The Right wire to the coil post.
5. The Left wire out of the box to the rear cylinder's coil post.
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We have yet to find the hot wire for the box.
6. Whereas a VOES wire is this wire out of the box.
7. The last wire is the ground for the box, but what wire makes the box hot?
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8. A (+) wire was attached to one of the coil's post. This now feeds one of the cylinder fire wires from the box to the coil. This is now that (+) wire that made the box [hot].
Where did that wire come from?
9. That is the alligator clip from the key's (+) side of the key switch.
Where did the (+) current come from for the switch?
10. The battery direct.
Make sense of 10 steps to wire a bike, hot which side of the coil to watt cylinder of choice and direction?