What the heck is this???

Well I took my stock seat and seat belts out of mine and its always started no problem, it had an annoying buzzer as well that I unplugged, if you look under the seat between the springs and the cushion there is a pressure switch that grounds out on the springs when you sit down. Then from there if you, or the passenger are sitting and the belts arent locked in the buzzer goes of and it will not start, I dont think the thing will even crank over, not 100% on that. Could it be the starter relay is bad? I know when I did my slant to v8 I changed the starter relay, nothing was wrong with it other than old. I also installed a new ballast resistor and battery cables. I was thinking maybe something to do with the neutral safety positioning switch...? But I am not sure, wiring and electrical are a PITA lol