Flickering head lights, what am I missing

To answer the other question. Yes, withthe wiring as shown, as long as the cutoff switch is on, the blue wires will be at battery voltage.
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If the regulator is calling for power, then the green wire will be connected to ground. In that case current will be be flowing through the alternator's rotor windings. In that case, the green wire will be something less than battery voltage - maybe close to zero. Otherwise it too will be at battery voltage.