Why did my temperature light come on today. 1994 Pontiac grand am. The gauge did not say it was overheating and out of nowhere my car stalled and the red temperature light went on?

You have two different temperature sensors in your engine. One is connected to the gage on your dash. The other is connected to your car's computer. The one connected to your car's computer either malfunctioned or a wire leading to it broke. When that happened, it told your car's computer that the engine had overheated.