74 Duster won't start

72_dart,
Do not bypass the NSS except for a quick test, and make sure nothing is in front of the car when you do that, like yourself. If the NSS is not making contact to ground (you can check easily with a multi-meter - brown wire going down to tranny from starter relay), that means the transmission is not in P or N. The NSS is doing its job protecting you. Work on your shifter linkage until the spring detents in your shifter match the spring detents in your transmission.

Also, next time post a question like this in the Electrical section. Indeed, search for info there first, since this question is regularly answered.