[projectRDM]

There is no neutral safety switch on any 240SX, period. The manual cars have a neutral position switch that merely relays to the ECU that the transmission is not in gear. It serves no other purpose.

On an automatic you have an inhibitor switch, it prevents the starter from engaging in gear and it a sealed one piece unit on the passenger side of the transmission case that relays inputs to the ECU for all gear positions. It can be adjusted if the car seems to hunt for the right gear or just not engage the proper gear selected, there's two M5 bolts that secure it to the case, the switch itself has some freeplay in the mounting tabs so it can be rotated slightly for proper adjustment.

Usually though in the case of an automatic having problems the O/D light will flash as well, there is a sequence for pulling transmission codes detailed in the FSM. If yours is not flashing I'd still run a diagnostic on it, it's found in the AT section and involves about 10 steps, that could possibly narrow it down. The inhibitor switch if found to be bad is the same for all models, 89-98, as well as the 90-96 NA Z32 and J30.