What I did with mine when I installed my Taurus fan was to get a Dc Controll electric fan controller (
http://www.dccontrol.com/). This controller I installed to the high speed wire of the fan. The controller has a wire to connect to the ignition (if it senses current in this wire, it allows the fan to run; otherwise, it will not turn on the fan regardless of the temperature reading). I connected this through a 3 postition switch, so the down position is AUTO, the center position is OFF (good for crossing rivers and such), and the top position, I connected to a relay (40A) to the low speed cable, so I can also override the controller and turn on (if the controller ever fails, I will not be left without a fan; I can also run it on low to quickly cool the engine if I need you). The controller also has a wire that you can plug to the AC Compressor, so the fan turns on when the compressor is on (if you have it).
I have left the fan in auto since I instelled about 2 months ago, and I have had no issues with it. What I like is that this controller actually varies the speed of the fan (the hotter the reading, the faster the fan will turn), and by doing so, you do not have the amps running up when you start the fan because the fan does not turn on directly to full speed but rather starts slow and gradually turns the speed up. The other day I was jump starting another car, and even though I had the engine a 2K RPMs for about 10 minutes without moving (in a windless setting), the Jeep never went past 210* (when with the mechanical fan, it would do so all the time). After a while, I decided to turn the override on, and forgot about it and left the Jeep running at idle, and when I got back to the Jeep, the temp was VERY low!
Anyway, just my 2 cents...
Felipe
