ProParts Water Temperature Gauge Type Controllers are all electric and microprocessor brushless stepper controllers. ProParts engineers added a built in programmable thermostat to control any temperature regulated devices from radiator fans to transmission fans. You can program the high and low temperature set points that you want the fan to activate and the gauge will control your fan. The fan turns ON when the high setting is reached and the fan will stay running until the temperature is lowered to the desire low release setting. The temp sensor is a 1/8-27 NPT with a water resistant electrical connector. All gauges will flash if sensor input is lost. To operate a high current load such as a fan or valve you will need option 722-14820 high current relay and wire harness.