I have a 2007 Chevy Silverado, with this same issue, I have changed the thermostat twice and it still keeps happening. Last Thermostat change the error did not happen for a few months but started up again and we finally have cool weather. Stopped unplugging battery to reset and when the weather is cold in the morning the temp guage will start up on it's own again, but the warmer the day gets or the longer drive the truck it comes back on, very annoying any real answers for the fix out there.