I wired my dual electric fans for high / low settings, using a GM Silverado wiring diagram.
Looks confusing at first, but if you break it down, circuit by circuit, it is a clever way to run the fans in series for low, and parallel in high. I also have it wired to activate the low circuit when the AC is on. I’m using GM fan motors so not sure it will work with aftermarket fans. ECM is set for stock fan temps, thermostat is 186. Hope this helps someone. BTW, I’ve tried stock radiators with both mechanical and electric fans, and finally went with a 4 row aftermarket Rad with electric fans. Works for me, your results may vary!
“We’re all Bozo’s on this bus!”
Cheers!

Looks confusing at first, but if you break it down, circuit by circuit, it is a clever way to run the fans in series for low, and parallel in high. I also have it wired to activate the low circuit when the AC is on. I’m using GM fan motors so not sure it will work with aftermarket fans. ECM is set for stock fan temps, thermostat is 186. Hope this helps someone. BTW, I’ve tried stock radiators with both mechanical and electric fans, and finally went with a 4 row aftermarket Rad with electric fans. Works for me, your results may vary!
“We’re all Bozo’s on this bus!”
Cheers!