If you are referring to the thermo sensor on the radiator which activates the radiator electric cooling fan motor, there is just a finger on it which must be lifted to unlock the plug from the socket and then just pull the plug straight out. It can be a tightly fit socket and might be hard to unplug if there was no dielectric grease used to lubricate the socket but it will unplug by just lifting the finger lock and pulling the plug straight out.