Not a mustang but I’m fairly sure they are all the same.

Fender mount starter solenoid. Am I correct in the thought that there isn’t really a wrong way to hook them up.

Small wires are the solenoid and large wires are the power to starter obviously but it Don't matter which small wire goes to which terminal correct?

Original on on the fire truck decided to blow open and burst into flames lol. Grabbed an off the shelf one from local parts store and won’t work.

I am getting power to the one small wire with the ignition on but key not in start. Do these switch the neutral threw the ignition or am I chasing wiring issues?