I changed temperature sensor, and now my fan will not turn off. Any ideas?

 

Something is going on and needs to be thoroughly checked out.

The idea of if the temp goes too hi , the fan comes on is not always true.
Some systems are designed to come on when any defect is present to prevent an overheat condition and destroy parts of an engine.
The circuitry is designed to be active and keep the fan from running when everything is right and if not working correctly, the fan comes on to prevent any damage.
Different manufacturers use different methods to control fan operation and in this case , if there is a problem keeping the fan off , it may stay on to prevent engine damage.