Is this a Dometic single zone LCD t-stat and was the trailer sitting in very hot temps? If so, then it's been an issue for a few years and there are solutions. Check out this thread starting at post 15 ...
In short, try cutting the power to your trailer. Also, try cooling down the thermostat with compressed air or a bag of ice. The t-stat needs to be below 110 degrees fahrenheit. Good luck.
Also, call your dealer and ask for a replacement.