OP – your thread title and your 1st post conflict a little, and for an electrical problem like this it’s easy to get the rest of us sidetracked if the specifics aren’t spot-on accurate.

LS-300 is correct on the ballast resistor clue, but I’d suspect the ignition switch also.

Neutral safety switch should only interact when cranking the starter motor, not at other times. If car will not start in park but will start in neutral then NS circuitry is to blame.