To expand on Steve's good advice in the last post, the way the fan works is one connection is at ground all the time, the other connection to supply power goes to a relay and when the relay is turned "on" the other connection of the relay is supplied power from 12v through the fuse, so the chain is 12v to fuse, through fuse, through relay to fan motor. The relay coil connections to turn it off or on is wired where 12v is always on one connection, the other connection is drawn to ground via the PCM to energize the relay. The coolant temp sensor is a temperature sensitive resistor that changes resistance with temperature change and is wired into the PCM.
So the basic way the sytem works is temp sensor sends a voltage to PCM, PCM uses this info to turn on fan at 221 degrees by grounding the relay, while the other connection is 12v, relay turns on. 12v is supplied to fan fuse, through fuse, through relay to fan, other connection of fan is always grounded so fan runs. When temp drops to 212, the PCM removes the ground from the relay, the relay turns off, fan turns off.
If the display is correct in reading temperature, as Steve said, the sensor appears to be working, and the problem would be most likely the relay or associated wiring.
Good Luck