fan controll with ac.

hello.i have a 99 silverado w/5.3,ive added electric fans about two years ago.took off manual fan and added the dual spal fan setup,they are controlled by an adjustable temp controller from autozone with a relay thats connected directally to battery(fused)with a switch on dash to run fans whenever i want.
setup works great,no problems other than one improvement i would like to make.i have no a/c controll.i would like fans on at idle or slow speeds(with ac on),i dont want fans on all the time even when im traveling on the highway/roads.air flow through grille at highway speeds is better than /and more efficent than the fans.where/how do i find a trigger for fans(relay) with ac on and go off at highway speeds like an oem setup????ive always used my switch for this,i dont want to forget and blow something in the ac system.
is my computer capable of controlling fans if i add the pin to the computer plug that ive read about newer models if so, which pin/color/location? thanks,Gary.

Allen Nelson sells a harness that should plug in and work with the fans.... as far as coming on at certain times im not to entirely sure how that works.... i would assume that you can control them through the computer after using the harness... check with Allen (farmtruc) or someone else that has efans (i will soon but not yet) and they should be able to tell you all you need to know

I'm just thinking that going down the highway your fans would being spinning from the wind, kind of like a windmill. They should come on w/ the a/c I agree, but I can't see waisting all that energy trying to turn them off at highway speeds. I forsee minimal returns for a tedeous investment.

<div class='quotetop'>QUOTE(daredevil350 &#064; Jan 2 2007, 02&#58;20 PM) [snapback]78089[/snapback]</div>

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I&#39;m just thinking that going down the highway your fans would being spinning from the wind, kind of like a windmill. They should come on w/ the a/c I agree, but I can&#39;t see waisting all that energy trying to turn them off at highway speeds. I forsee minimal returns for a tedeous investment.
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i agree but,i would like to save the life of the fans.the only thing i can think of is a vss signal or the cruise control system will only engage at a minimum speed,maybe something there?