Argument needs settled. Back up lights.

If your neutral safety switch has 3 prongs and the wire connector has 3 wires then the it's also the reverse lamp switch. If it has one wire than it's just a neutral safety switch.

The two outer poles of the switch are for the reverse lights. If you have continuity through them with the shifter in reverse then the switch is good. Make sure the linkage is also properly adjusted. The center terminal just grounds the starter relay when the shifter is in park or neutral.