Coolant temp gauge only comes on now and then. Is this a bad sensor? on 2007 Chevrolet HHR

does this need cleaned? The a/c does not work if the coolant temp gauge is not working.

Asked by for the 2007 Chevrolet HHR
sounds like a bad sensor to me ,have it scan tested to get the right temp reading
Thx Goodguy, Where is the sensor located?
1 more answer
I had the same problem. I replaced the thermostat and that fixed the problem. The new thermostat will remain open when they mess up. Mine also said coolant temp low. Hope this helps.