How does a neutral safety switch operate?

[dfrazz]

On my '71 Challenger with a 727, I am hoping for a little assistance with my neutral safety switch before I just go buy another one.  I am wiring my NS switch and have the brown wire going to the appropriate location on the starter relay, but that location only works when it receives a ground current (ie trying to start the car, send a ground current and the starter relay clicks over to start).  When I attempt to start the car, the brown wire is sending a positive current which is not triggering the starter relay.  I understand on the NS switch that when the button is pushed in the reverse lights are not on, and when out they are on (assuming the button is in for all gears except reverse so the lights come on). The NS switch has three prongs, 2 on the outside sending positive current to the 2 black wires to the harness, and one in the middle that I believe should be sending a ground signal when I attempt to start the car so the starter relay clicks over.  Is this correct? How does the NS switch know when to send the ground in only Park and Neutral to allow me to start the car?  Am I missing something or do you think it is a faulty NS switch?   

[Chryco Psycho]

Correct , the 2 outer pins are in & out for the reverse lights so it doesn't matter which wire goes to which side , the brown is the ground for the relay , there is an outer pin & an inner pin on the switch the outer pin is only depressed in reverse , the inner pin is depressed , only in Park & neutral allowing the relay to trigger the starter . The brown wire in the center of the switch should never have power , it is just to ground the start relay , if the brown wire has power maybe there is a short in the harness somewhere connecting with the power wire for the reverse lights .
 I hope this helps