Just because the main red power feed wire from the battery to the ignition switch has it's own fuse, I don't think that's going to eliminate the feedback problem. It has nothing to do with that main red wire. The feedback happens through the headlight on/off switch if it's switched on while the bike is in "Park", sending power back to the fuse box. Since all the secondary fuses branch off of the same power feed wire, pumping current into one will spread it to all the others. Since the blue tail light wire coming out of the on/off switch connects into the blue wire coming out of the ignition switch and running to the tail light, giving it power from the ignition switch (Park position) will feed that power back to the headlight on/off switch as well. We need to stop that and that's where the diode comes in. It's like a one way valve, allowing power to flow in one direction but not the other. You place it on the blue wire coming out of the headlight on/off switch so that it allows power to flow out but not back into the switch. Feedback problem solved.