How does the lighting circuit work on the Alt,Bat, etc. Typically, potential volts (12vdc) into a load (light bulb) to common or ground will control the light. Does the Alt curcuit have a high impedence resistor or something to allow dash light to be on when ignition is "on", then light turns off when engine is running and then turns from dim to bright as Alt ot Batt loses voltage? can you clarify please and thank you.