First of all, please read the signature requirements topic in NOTICE.
Secondly, you have TWO coolant sensors. One for the gauge, one for the PCM to control the fans and other temperature dependent functions. My first suggestion would be to check the resistance of both sensors at the same temperature (one cold, one hot comparison between the two) and make sure they're reading close to the same.
Temperature vs Resistance values are listed in Techinfo for IAT and ECT sensors.
Thirdly, if your car gets that hot, simply turn on your AC. After you do, pop the hood and visibly verify that both fans came on high. That'* a default state the PCM commands when the AC turns on.