I'd rather have mine on more than needed than have it off and forget it's off. I didn't even notice when the junkyard motor's brushes wore out until my check gauges light was on- looked at my digital dash and it was at 255 and trans was at 220. I shut it off then and there.

 

That's exactly why I only put the switch on to interrupt the a/c feed to it, that way it'll still turn on if it gets warm and I forgot to flip the switch.

 

I have to ask, what is the point in disabling the A/C flow? I just let mine run....I usually turn it on around 125-150 if not first thing when I get in. It's set to come on at 190 with 180 Tstat, if I turn it on by hand water temp stays around 174.

 

When you're going above 40mph or so there's enough air going through the radiators already (more than the fan could push too), so I shut it off the a/c trigger to the fan controller on the highway because it's just wasting power to have the fan running then.

 

i would think it's just freewheeling. If anything, the fan is turning extra RPM actually becoming a generator...but I have no data to back this up.

 

Generator. Lol Good one.

Mine was Auto on. I set for 210. My thermostat was a 195.
Manual on and manual off.

Yes, one could forget to turn it on. But you'd really have to not pay attention to your truck to not notice it getting warm.
I'm sure like me you guys pay attention to the vehicles you drive.

 

But if your luck is like mine you'd get distracted for a minute and then bad stuff would happen.

 

In a hurry. Lol.

 

Well guys, I think I found the real problem. I got some 70 amp relays and redid the wiring and let the fan run for a few minutes and the fan motor started smoking. I think it's time for a new fan lol. Now I have to decide whether to go with another Taurus fan or run a Lincoln. I have a Mark VIII fan in my Ford and that thing is pretty powerful and not sure if I need quite that much. I might rewire it and just do 10 gauge while I'm at it too.

By the way, if anyone needs any good relays, hit your local pick a part... I picked up 2 70 amp relays off of a Ford Focus (Crown Vics and a bunch of other cars have them too) as well as a bunch of those box style (expensive) fuses for $4 and some change.

As to the discussion about switch vs key on vs thermostat... I have mine fully manual on a switch and I have definitely had times when I wished it was on a thermostat (which I'm going to do this summer, as other people are going to be driving it soon). I pay very close attention to my vehicles while I'm driving them, but when you're up to your shins in mud trying to get your truck out of the mud, you don't always remember to flip on the efan. Got back in there just in the nick of time and got it cool.

 

Yeah, I'd say that's your problem The depo one I had did that exactly a year and a week from when I got it (isn't it funny how warranties work like that), so I just grabbed one from the junkyard for a couple bucks and have been using it since August.

I prefer the taurus fan because of the dual speed (I'm not sure if the mark fan has it or not to be honest) that way it's not on all the damn time at high speed. I do have a dakota digital fan controller to manage the dual speeds too. I see the newer version of mine has an option to turn off the fan at highway speeds which I would have liked too. http://www.dakotadigital.com/index.c...rod/prd852.htm

I forget where but a while back I saw a graph somewhere showing the cfm vs current draw of the two fans, and while the mark iv fan moved a couple hundred more cfm of air, it used way more power to do so, so I don't think it's worth it. Here in sc I've been stuck in traffic in 110°+ heat with the a/c on, and the temp never got above 190° or so (I have a 180° thermostat), so I think the taurus fan moves more than enough air.