I have two alternators that check out good but they don't get the signal to turn on and charge. External voltage regulator is good. Could the be a problem all the way back in my ignition switch assy?

 

could be. Pull plug and check terminals at alt to see if current is being sent from ignition. Could be poor connection, broken wire, ignition switch, prior to ignition switch. Pick an end of circuit and test a long the way.