Need to have a look at this tonight again, sorted it the other day by messing around with all three of them, but I'm not sure which one is and the problem has come back again. Does anyone know which colour wires should connect into there, i presume it's not connected to all 3???

not critical but i kinda want to be more efficient by not messing around with the other wiring too much, and the ECU is seeing double RPM according the the secs monitor so i need to sort it out.