A couple years ago or more, 3.8V6 2 speed Taurus/Sable fans were popular
and do a good job cooling. They could be had for around $50 used, but
probly most of them have been bought up.
Also popular for real heavy duty cooling were the Lincoln Mk VIII fans which
moved more air but drew about the same amps due to a more efficient blade design.
That's what I put in my 5.9 Durango a couple years ago, run by a
Flex A Lite soft start variable speed controller. Works great.
http://www.summitracing.com/parts/FLX-33054/
I absolutely would not run a heavy duty electric fan any other way.
I guess the latest popular one is out of HHR Chevy's and can be had new
at Rock Auto (look under radiator, fan) for around $60. Not sure, but have
read 1 post that said it doesn't draw much for amps so you mite be able
to run one with a simple Hayden thermostatically controlled on-off switch
which are inexpensive and easy to wire. I read a post where it was claimed
that even guys with hopped up big block 4x4's were using them off road with
good results.
Best place for a probe type temp sensor, if you run it that way, is right
by the upper radiator hose coming into the radiator which is the hottest
point in the radiator.
Just FYI here's my Mk8 install. I've got a big trans cooler in front of the
radiator and have pulled near 6000 lbs loads at freeway speeds in hilly territory
at near 110 temps with no problem. Most people probly wouldn't need that much
cooling capacity.
http://www.mediafire.com/?8wafwzb583ka5
I put in a set of gauges to make sure of what was going on, and here's what
I found to hook a temp sender in.
http://www.mediafire.com/?cbb1zahcso0d5
The little red LED in the gauge panel comes on when the efan is running.
Just wired into the wires between the controller and the fan motor.
Got it at radio shack.
The gauge doesn't show much movement until the thermostat opens,
but then that tells me for sure that the Tstat IS open and when that happens.