1990 Dodge Spirit car won't start

Need a better description of the symptoms and what was tried already. "Doesn't start" can mean a lot of different things. Do you hear a single rather loud clunk from the starter each time you turn the ignition switch to "crank", but it doesn't crank the engine? If so, that has an inexpensive fix. You said the "starter relay switch was replaced". Are you referring to the starter relay or the ignition switch? What led you to that and what was the result? You also said you ran a power wire directly to the starter. To which terminal, and what was the result?