is it the temp control sensor thing?

 

It could be the thermostat is stuck open. Try replacing that, its cheap and easy.

 

Replace the coolant sensor. There are 2 one for the comp. and one for the gauge. The gauge has one wire on it.

 

If you have the $$ replace both the sensor and thermostat that way you know you have new functioning parts. If you replace the thermostat make sure that you get and new housing gasket and to scrape the hosing and the manifold of old gaskets. Leaks are never fun. Install the senor first and see if that does the trick and if it doesn't then its the thermostat or than liley. I think when i replace mine all it cost me was are 12bucks for a thermost gasket and a gallon of 50/50 antifreeze, i replaced it right before winter.

 

What i always do is take the wire off the sensor put it on a ground turnkey on see if your gauge goes all the way to hot this confirms that your gauge is good,Then replace the sensor but check the gauge first