question on bulkhead connector bypass

Dave NEO said

I'm on a mission to learn more about this overall system and any mods that can improve it short of replacing the harnesses. Looking at all the diagrams is one thing but understanding how factory intended it to work is something else. Right now I'm thinking why did one side of VR go to ignition circuit? could it have gone elsewhere for the purpose that terminal served. IS going direct to the positive battery post essentially the same thing. I appreciate the knowledgeable people here who sorta stick their necks out a little answering questions, as there are often some differing opinions ,or at least more than one way to skin a cat..

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Anything wired directly to the battery is on/hot at all times. You don't want create battery drains. There is only 1 switched hot source in the engine bay. That's the blue wire from ignition switch. At switch on it energizes the voltage regulator/alternator field and spark/ignition at minimum. It might also supply IVR and some warning lamps inside in many models.
In later models it also supplied everything they added in the engine bay requiring switched 12 volts. Electric choke assist, idle stop solenoid, etc...
If you can't get sufficient current though the ignition switch and out to the engine bay, the blue wire could energize a relay out there ( The same remedy applied to the headlight circuit ).