Google.com rocks.
http://forums.freshalloy.com/showthread.php?t=155414
Or using factory:
http://www.nicoclub.com/archives/wir...to-an-s14.html
My personal setup has the one side on low speed all the time, triggered via ignition switched 12v power. The other side comes on high using the Derale controller. Never ever have had an issue. Some people do not run either fan until a sepcific temp, but I opted against that in lieu of having the one on low all the time.