On our Mopar ignition switches there are 3 separate terminals for starting and running.
IGN 1 is the run cir
IGN 2 is the ballast bypass cir
START is the cir that triggered the starter relay.
IGN 1 feed 12v to the ballast resister when the engine is running.
IGN 2 feeds 12v to the coil side of the ballast resister during starting
START feeds 12v to the starter relay
If you remove the ballast resister IGN 1 and IGN 2 need to be tied together.
For a test.
Disconnect the yellow ( on a 67) wire from the starter relay.
With the key in the run position you should have 12v to the ignition switch side of the ballast resister or the wire that was attached to the ballast resister.
With the key in the start position you should have 12v at the coil side of the ballast resister or the wire that was on the coil side of the ballast resister.
The yellow START wire should not be used for anything else that the starter relay.
Hope this makes sense.
Just trying to rule out incorrect wiring.