NY01ws6

i have a 1995 formula and the electric fans do not come on i check it out the best i can without any diagrams but i cant figure it out. It has a switch wiried into it to control the fan that im taking out and tring to make it work properly. the fuses are good and the relays are good i also bypassed the input of the relay to check the circuit from the relay to the fan and the fan comes on so im missing the input to the relay the relay has power to the control side and when you jump that out the fan works it also has power to the input side but im missing the ground signal when it reaches oper. temp. does anyone know where the ground signal comes from and if not maybe anywhere to get a good wiring diagram online????