I have a temperture gauge that is reading almost HOT almost to the red. on 1997 Ford Expedition

I have a temperture gauge that is reading almost HOT almost to the red. But when I lift the hood It's running OK and doesn't seam to be hot at all. I think its the sending unit or the gauge what would I check first and How

Asked by for the 1997 Ford Expedition
3 answers
You could have defective coolant temp sending unit or the computer might be acting up.
Also, the thermostat may need replaced. It may have froze up in the full open position.
have you thought about replacing the "thermostate" their are ones that you can purchase for a few dollars that will run cool when its hot