thanks for the info Bob. I am going to run 2 relays...1 for each fan. Hot will be wired waiting for ground from either temp sesor t-d into heater hose onnection at pas side of intake, or clutch switch, or trinary switch Old Air products has in their kit, or a manual overide switch in the dash for a sensor failure. Still thinking on the overide switch...might make it hot 12v straight to fans using a 40 amp toggle switch for a relay failure situation. Yeah, can't get over the sticker shock on those DCCs! I would like to see the dual speed circuit you came up with...I like the idea of be able to operate the fans at 1/2 speed. Don't you have to rapidly increase and decrease the volts to get a 6 volt avg to do that with out burning up the fans like a straight 6vdc would? Thats why the DCCs cost because they are varying the voltage really fast....thats my understanding of it.