1968 mustang starting problems

i have had a 1968 mustang for 11 months so far. it has always started right up. i put in new guages and i think i might have put in the clip backwards for the guage harness but the car started up. i shut it off and left it for a few hours. i went back to start it again but it didnt work, when the key is in the on position, lights and radio worked as usuall but when i went to crank it nothing happened. what could this be? i put in a brand new ignition switch and it still didnt work.

oh and i put the guage wiring harness the right way in, what could i have burnt out?

Under the hood, follow the positive battery cable to the starter solenoid. With a jumper lead, connect (momentarily) the post where the battery cable connects to one of the smaller posts. The starter should engage. The wire that connects to the small post you jumped goes to the “start” contact on the ignition switch. Find out what is wrong, the solenoid or the wiring that connects it to the switch…

yes that starts it up but when i connect it to that, i put in a new solenoid and as soon as i connected the battery the car started on its own so i think the new solenoid is broken, all the wires are hookedu p exactly the same. i ut the old starter back on and the car started normally again, then i ran it for 15 minutes and when i tried to start it again 20 minutes later, the same problem all over again. one of my thoughts is a bad solenoid but i dont want to go buy another new one and another though is the neutral saftey switch is fried… what do you think?