Welcome to the club Luis. Not knowing any info on your vehicle, the easiest thing to check would be the wire going to your temp sensor on the engine. They can sometimes work loose, & the older your veh is the dirtier the connection can get too making for no continuity.
I would say its a bad temp sensor. I work at a parts store and this happens a lot. People come in saying that there temp gauge is stuck in a cetain spot. Once they replace the sensor it fixes the problem. There usualy something like 10$. Try that and check your wire connection on it. It's usualy only 1-3 wires on the sensor.
A forum community dedicated to all General Motors truck owners and enthusiasts. Come join the discussion about performance, lift kits, wheels, tires, modifications, troubleshooting, maintenance, and more!