I'm guessing that this is the thermostat that you have.
https://www.campingworld.com/images/...structions.pdf
Set the mode to 'Cool", then press the "Fan" button until it shows "Auto". Then, push & hold "Program & the down arrow at the same time, "diF2" should display on the screen. This will set the temperature differential to 2 degrees from your set temperature before the A/C or heat turns on.