Trouble with temperature gauge

[redhead59]

Need some ideas to a problem. I have a 1996 Grand Am SE v6.
The temperature gauge is raising and goes to the 260 and red light comes on. . Had battery problems put in new one. But still the gauge goes up.
There is no heat and when driving the car is not overheating.
I am thinking thermostat or a sensor!!! But need to know if driving it this way will cause more problems?
Please help !!

 

[melsg5]

have you checked the coolant level when cold? No heat would indicate low coolant or a thermostat stuck open but that would not cause the guage to read high and the light to come on.

 

[redhead59]

coolant levels are right on the money on cold. Have checked all of that thanks. Never thought that the thermostat stuck open. But in driving it does not heat up. Wanted to know if this could cause more problems??

 

[melsg5]

a thermostat in an open position will cause poor gas mileage and other drivability issues but that theory does not explain the high temp reading and the light. It could be a combination of a bad sensor and stuck thermostat.