Well, the first step for me is to find out whether the fan is actually running "excessivly" or not. By that I mean, is it running anytime when I wouldn't want it to be on. That goes back to my original question. Before I fiddle with anything, I want to know how much room there is for improvement. If the ECM is already doing a fairly decent job, then it's not worth messing with.
Slowmover, here's just a thought for you. Could you replace your mechanical clutch with an electrical one rather than going with a entirely electric fan? The challenge as I see it with that though would be controlling it (since your ECM isn't set up to do it). Of course you probably could do it with a manual switch all the time but that would be a pain (and a risk that you might forget it). Here's another option though: those electric fans must have some type of controller, so maybe you could use the controller from an electrical fan and put it on an electrical clutch. Just a thought. And keep in mind that electrical stuff isn't my strong suit.
