Neutral Safety Switch

I got my first Grand Prix and the previous owner had a push button start put on it to bypass the neutral safety switch. I changed the neutral safety switch and it still wont start with the key only the button. What else could I check. It looks as if the wires from the push botton go from the button to the battery then to the starter.

What year grand prix is it? It could be the neutral safety switch is not adjusted correctly, the ignition switch, a wiring problem, or a couple of other things.

Maybe it wasn't a neutral safety switch. Could be security or just a general fault in the circuit. Treat it as a no crank no start and forget what the PO said, it may not be the actual issue.

Being that you say you changed the switch, that means it's a external. There is a dot that needs to be lined up in neutral in order for gear selection to be correct.

Pictures and explanation of the dot/alignment is in this thread.
http://www.grandprixforums.net/showthread.php?t=49297&highlight=easy+external