There are two connectors at the back of the valve cover. A 2-pin one, behind the choke cable there, I have discovered to be the thermo switch for the carb fan. The other one is 3 pins. One pin is to the fuel cutoff solenoid. One pin is to the thermo switch in the head. What's the 3rd one? It seems to have a couple volts on it with the ignition on.