Thanks Jody!!
You confirmed what I thought... Your instructions/ideas - is exactly how I run my Accel DFI system - but it has an A/C input - so was trying to see if the Fast EFI used this as well.
Living in the great Pacific NorthWET we have very few cooling issues... and I've been using the Accel to control both fans with a stepped / overlapped ECT. But using the ECU to only control ONE fan on with the A/C... but maybe I should be turning both fans on when the A/C comes on and will look into that. That might help the cooling (A/C) when the car is in Reno (Hot August Nights) and we're just tooling around town in stop and go traffic.
Right now - his system is using a Binary switch - but I have to make him all new A/C hoses anyway - so will put in a Trinary switch when I do.
