20. The fan relay connector comes pre-wired, meaning you only have to connect three loose wires for each relay. The large orange wire connects directly to the battery (this feeds the fan power when the relay closes), the green wire connects to a switched ignition source, and the gray wire connects to the included temperature sensor. When the temperature sensor reaches its set point, it grounds the gray wire, turning the fan(s) on. The wires are also screen printed for easy identification.