Hello.

This may be of use to those interested in custom-installing a pair of efans.

LS1 fans are connected in OEM applications via the following circuit to provide low speed / high speed functionality (and the attendant benefits of lower startup inrush currents) using only single-speed fans.

All that's needed in addition are two controllers to provide staged setpoint outputs, or a single controller that does the same...



Hope some folks find this useful.


MGD v5.0

 

I used to make such a circuit for running dual cooling fans. However you need an IFB (Interface Box) to do it properly since your connection at the computer would be different.
I' don't know (too lazy) how to display a circuit diagram on this site, but if I could I would show you the Controller IFB for the three relay circuit. I had several circuits the went between simple switching, electronic control, thermo-control which I set from my dash top.