My idea was to use the water in the heater core (constantly circulating) to kick the fan on just barely before the t-stat opens up to minimize fan usage and current drain. More miles from my junkyard fan + I don't sacrifice cooling

 

True, I would think there would be a bung somewhere on the head or like my 4.7l right on the tstat housing.. Just a cheap way of doing the same thing.. I figure if they put them in a factory vehicle they ought to be reliable enough to not worry about failures....

 

Well the adjustable thermostat controller was only $30, so it's not like it's a real big expense. It's been in the truck for about a week now and no problems whatsoever. The fan works great, and cools the truck perfectly. I even got to tow my trailer around the other day and never had any issues.

 

I've got a Hayden 3765 (think that's the right model number) and mine kicks on at 180* and maintains it at about 188*. Keep in mind I also have a 180 stat.