need ideas (94 DODGE CARAVAN)

I have a 94 dodge caravan, that don't want to start. I have changed the starter twice (junkyard parts) and checked the wires, still will not start. What should I check or replace next to possibly make this van start.

Need more info. I'll take it when you say it will not start, you are saying when you turn the key the engine will not rotate. Are you only hearing a click or nothing at all? If you hear a click, the ignition switch, neutral start switch and starter relay are working. In that case you likely have a weak battery or poor battery/starter/ground connections or starter solenoid. If you don't even hear a click, your battery is very weak or dead or you have a bad ignition switch, neutral start switch, starter relay, starter solenoid or an open in associated wiring. Let us know those answers and do you have and know how to use a multimeter?