Here is a thread going on right now on 73 79 forum on electric fans.....

https://www.ford-trucks.com/forums/1...-viii-fan.html

 

Just like this but run temp switch to batt

and one more relay for the other fan and you're good to go incase one fan fails, the other still works

 

here ya go

 

also run some LEDs off the relays to inside of your truck and mount on your dash. When fan turns on LED is on.

LED off = fan off

 

like this then?
i would keep the temp switch on the keyed power so it doesnt have the load of the fans on it

 

Why 2 temp switches?

Look at my pic..

And as for the temp switch being keyed.

Run it straight from 12v batt side. There is no load from fans straight from the batt.

It goes from batt to relay to fan.

The whole point is to keep the fans running if you shut the truck off and it can still cool down. Similar thing race car drivers do when they pit and shut the car off. They either have e-fans going or pour cold water pver the radiator fins

 

its also not needed tp run an in-cab bypass.

More wiring than needed.

The whole reason to run the fans independantly is to have one still working if one goes out. Thus eleminating a bypass

 

my thoughts on the temp switch being in the keyed power is so if the temp switch sticks or what not then it will turn off when the key is off not keep going and draining the battery... our mechanical fans stop when shut off so i dont see a need to have the electric ones continue these trucks aren't race cars, i could see if the motors were heavily modified but not on a stock motor. the in the cab switch is yet again a safety in case the temp switch fails.

the diagram you pposted has the temp switch on the keyed side as well.

 

oh gotcha homie...

In that case, a temp switch made by a reputable company will do the best.

I got an Imperial 226203 temp switch/adjustable thermostat from Advanced for $15.

Imperial makes OEM e-fans so the temp switch should be just as good quality

 

does your switch have the little probe you put between the fins on the cooler?

 

Yes, its a fin probe, mounts behind radiator. I was confused between thread in probes and fin probes, but It doesn't really matter I found out. As long as you set the switch to kick the fans on when the truck is at operating temp.

It also doesnt go "in" the fins, it mounts close to the fins with a plastic mounting strap.

 

MT = mounting tab
Rad = Radiator
Prob = Probe

 

fan clutches are only so good.having the fan on there uses power and fuel even when the clutch is not engaged.
when it does engage,it's not efficient either.you may not need the full cfm therefore wasting fuel.
there are also other advantages.
a quicker warm up time which helps saves fuel.
any off road type working with the truck,you can have a lot more air flow than the stock provides at lower rpm because high rpms are not required to get it.
with the fans on the diesels,the stock mechanical fans are such energy hogs,that some owners claim they feel a seat of the pants hp reduction of about 20hp lost from the rear wheels.
with the e-fans on,and my truck loaded up i feel no power loss with the e-fans on,so i don't get bogged down going up hill like factory idi diesels.
swapping to e-fans isn't just for race cars.
trucks should have come from the factory with electric cooling fans for at least 20 years now.just because they don't do it,doesn't mean they can't benefit from the swap.

for those interested in maximizing the efficiency,you may be interested in a variable rate controller rather than simply on/off.they make the fans spin only as much as required.this is the route i took once i realized that the dual ford windstar fans were simply far too much when just turned on high all the time (diesels have extra large cooling systems,that are very easy to keep under control.be it just 8k lb empty or when hauling + towing close to max weight rating of the truck.)
having the e-fans with the plow on.....priceless. which reminds me,i guess i got to get out there and start pushing some white stuff around.

 

I agree 100%.
What I meant was our fans don't run after the truck is shut off...

So why wire an electric fan to keep going after the key is off. Which is why I put mine on Keyed power. In my old truck and intend to do the same on this one.

Realistically once the water pump stops turning when keys off and if the e-fan kept going all your doing is cooling the rad not the block anyways since there is no circulation

 

Count me in too...my fan's turn off with the key