Well, a '72 has no neutral safety switch for the manual transmission. I suppose you could wire one in using the auto trans Inhibitor circuit. A factory manual trans 240 will not have the inhibitor components - but you do.
I'm with "cats" on the trans switch locations. Early through ZX, the stock L-series 4 and 5-speed trans have a reverse switch location on the right side. I would ask what transmission you have? Easy enough to test the left side switch - "ohm" it out. Move the trans through the gears and see when the switch "is made". If it's closed in neutral, there's your neutral switch. If it's closed in reverse, there's your reverse switch. If it's closed in 6th, there's your top gear switch...
Pics of the manual trans may have helped.
1974 "early" 260Z - L28ET - MS3X full sequential fuel and spark, COP=Ford 4.6 coilpacks w/ Nissan Ignitor, diyautotune chopper wheel - FMIC - T04E .63 A/R - 400cc Injectors (too big!), 14point7 Spartan2 Wideband - C/R 5-speed - Coilovers - Big Brake Kit up front, Porterfield friction all around. Mesa, AZ