Ok first check if your comp. is throwing you a code by pulling up the carpet on the passinger side floor turn the ignition on and look to see if your getting 6 flashes through the window if you are check your fuse it will be in the fuse block under the steering column, I think it is the second fuse from the left I think on the top row. If that is good then start your car take the radiator cap off and see if the coolant in you car is moving if it is then your water pump is working. If you are getting 6 flashes then chances are your sensor is bad since you say it stays pegged all the time, I would think that if the gauge itself is bad then it would never move from cold. I would change the sensor first then if that dosen't work then the gauge, the sensor is about half the price............................................. ..let me know how it goes.