Not getting 12 volts to coil

WILL NOT PROVIDE POWER TO THE BOX
True but Bewy did not say to remove power anywhere else. All that is being done is providing a positive battery voltage to the coil during start. Run voltage still might be low due to voltage drop, I would add a jumper from battery + to blue (power in to the box) as well. That way the box and coil are both fed directly from battery.