195 Degree Thermo-Switch, Relay & Harness This easy to use cooling fan relay kit includes a labeled wiring harness, 40 amp relay, fuse holder and coolant sensor. Available with 185° on/165° off or 195° on/175° off. Works great with the Spal Pulse-Width Fan Controller. Relay wiring kits are a must-have when installing an electric fan. Designed to safely integrate with OEM wiring. Waterproof 40/50 Amp relay. Printed wires (for ease of installation) 3/8" NPT (National Pipe Thread) stainless steel switch. Optional switched override capability.