1966 valiant ignition problem

Got a test lamp ? 2 smaller wires on the starter relay. One of them ( yellow I think ) gets 12 volts every time the switch goes to start. The relay will only energize to run the starter if the neutral safety switch is supplying a ground path on the other wire ( brown I think ). If you prove start signal from switch is good, put a jumper to chassis ground where the other wire is and it should start,( even when in gear so be careful ).Start hunting the neutral safety switch problem. If the start signal isn't good, the problem is from there back to the ignition switch.