You should have 2 wires on the + or ign side of the coil; one from the ignition switch via the ballast resistor and one from the starter. That connection will read +12 volts with points open and around six volts with the points closed when not cranking on the starter, 12 volts at all times when starter is engaged (-2 or 3 volts from starter drag). The - or dis side side of the coil should be wired to the distributor and should read around 12 volts with points open and zero volts with points closed. That is the complete low tension circuit. If you don't get zero volts on the dis side of the coil with the points closed you will get no spark.
