Re: entropy fan issue
You buy the one that switches at the temperature you want. I use a 90°C switch from a BMW to trigger my fan to low speed. You can test the switch in a pan of water on your stove. Put the thermoswitch in a pan of water cooler than the trigger point and slowly raise the temperature until it triggers.
You can't use a temperature sending unit, as these are meant to drive a gauge.
"For those that will fight for it...FREEDOM ...has a flavor the protected shall never know."
Semper Fi! L/Cpl Edwin L. "Tim" Craft, B Co 3rd AT's, Khe Sanh Combat Base, February, 1968