You fellers misunderstood me?

I believe all the conditions are met - just drive a normal relay whose N/C contacts are inline with the signal that is enabling the A/C fan function.

 

Well curiosity got to me,or maybe being a bit hard headed. I got the rpm switch from summit,tapped it into the vss signal at the cruise control servo,made a few adjustments to the device settings,installed a relay and it works!!! I can set the fans to go completely off at any speed above 35mph. I still have the temperature controls in place for when in traffic or a/c on and below set speed. I simply allow it to remove ignition power from fan controls.
I only did it this way because even with fans set at 220(a bit high for my liking) the fans would still cycle on/off when at highway speeds,not a huge deal,but it just wears them out faster and they're not needed at speed....so yes,it works!!

 

Thanks for the Great feedback and Well Done !!!

Folks now have another option for implementing this feature.


MGD

 

Thanks for the update

I'm real interested in some type of automatic efan-delete-at-speed system. The only complaint I've had about my current efan setup is the manual switch I installed to shut the efan off when using the AC at speed. It appears you've devised a pretty good solution.

 

Ok here's what I did.....the efan controls are from derale,set at about 217 on,200 off.I have 2 of them,just to be a bit redundant. To turn on fans for a/c,I simply tied high side a/c pressure switch + wire into the derale controllers driver override command wire. This way the fans are always on with a/c on regardless of coolant temperature. I did have another thermal control for when a/c on,but its not needed now.
What I did for turning efans off at 35mph was I got this from summit... SUM-830450-1 ...
I attached the device trigger in wire(gray) to the 2001 Ford f150 oem black and gray wire at the cruise servo(it might be different colors,so check your model wire diagram). Put the device on 8cyl mode,adjust settings to 1100 pulses(device instuctions will explain how to install and adjust,but remember your not going to any engine coils,crank sensors,etc...). Installed a normally closed relay(it will have 5 spades not 4) in line with ign power to derale efan controllers. Attached the ground signal (the blue wire) out of summit device to relay ground (on/off) control so when vehicle is at speed it will activate relay thus removing ign power from efan controls and shuts off all efan operation at 35mph.
You can set at higher mph if you choose,or play with different settings to really fine tune device to an exact mph.after i installed device, I just jacked back wheels up and found number of pulses to mph I wanted and made it my setting.
I mounted it in engine compartment,but its not weather sealed,well it is now with a bit of silicone.
This will turn efans off when you reach your set speed.
The rest of efan controls work just the same as before when your below your set speed.
all other oem stuff works just as before install.
I hope this all makes since, feel free to contact me if I can help.

 

At 70 mph, there is so much air being crammed through that radiator that the water is getting completely cooled. It won't get anywhere near 220 at speeds over 35 mph. Congrats on the success, but the only time they would be on without your gizmo would be with the A/C on, and even then, they would be free-wheeling in the motors.

 

That's the whole point - to turn off the unneeded fans and their current draw - at speed.

Freewheeling efans draw no energy and are irrelevant - even the stocker freewheels to some extent.

It's a great mod - and my belief is that ALL efan kits should have this functionality OOTB - as it is, only Painless and MAD do, AFAIK.


MGD

 

Correct, there is plenty of air over 35mph,so I just wanted to be sure efans are off. It's extra electric draw and extra wear on the semi expensive fans. It's just a win all the way around.