The more I think about it the more I think I can "trigger" my electric cooling fan with the temp switch that is already in the truck with out buying any additional parts or kits. I have a 5 post relay and the cooling fan............the real question is can you use the temp switch to trigger the relay and power the cooling fan? I know that the temp sensor is a variable resistor type....so does it have little to no power when cold and as it warms up "allows" power to go to the potintiometer(sp) i.e. temp guage? or vise versa??