I bought a "185 degree on" electric fan sensor, but, according to the temp gauge, the fan cut on at about 165 and stays on prettymuch all the time once it cuts on. This is the second fan sensor I have bought because the other did the same. I just thought it was a bad sensor.

The temp sensor and the fan sensor are mounted about 6" apart on the intake. Which one should I trust and which one should be mounted near the thermostat?