SPAL DUAL FAN WIRING DIAGRAM
Wiring Dual Electric Fans - Speedway Motors
Other methods that I have used to wire up dual fans are using single relays to control both fans. I have found this to be inefficient as most dual fans pull enough load in amps at start up to blow the fuse for the relay. This should be around a 30 amp fuse in order to protect the wiring and relay.