what is the small wire to the starter

That is the wire that turns on the starter solenoid, this wire comes from your ignition switch. So if that wire has no power when you turn the key, something in your ignition switch circuit is defective.

the small wire is the solenoid wire. when you turn the key thats what sends the power to enguage the starter gear. take that wire off and have a friend turn the key forward while you use a test light to see if you are getting power to it. there should only be power to it when the key is all the way forward. if you have power then your starter is junk.

THE SAME THING ON MY FRIENDS 2000 DODGE RAM 1500 THE NEUTRAL POSTISION SWITCH WAS THE PROBLEM $20 NAPA STORE DRIVERS SIDE OF TRANS. JUST ABOVE THE OIL PAN