I have a 2001 Yamaha Big Bear 400. The cooling fan comes on as soon as I turn on the ignition switch. Thinking maybe the thermo sensor. I disconnected the electrical connection to the thermo sensor nd the fan still runs. Any Ideas?

 

Update, i unplugged and replugged in what i believe was the relay. the fan quit coming on with the ignition. Someone told me to unplug the connection at the thermo sensor with the ignition on and the fan should come on with it unplugged. I unplugged the sensor and the fan did not come on. I ran a jumper wire between the 2 connections in the plug and the fan came on. I guess my next question is when i unplug the connector for the thermo sensor with the ignition on should the fan come on?