Ac was not cooling. Freon put in last sun. Seemed okay. Now no ac only blows. Control button only blinks but will not turn on

Let's just assume that your a/c system had no leaks, and the refrigerant (should be R134a and not freon) charge still complete. Automatic hvac controls uses push buttons instead of the manual rotary knobs. Once you push a button for a particular function, the corresponding light will indicate on. Normally the light should turn on steadily once requested and enabled. If that light is blinking, it is just telling that the function you requested is not yet available at the moment, even if you pressed it repeatedly. Why? It's because the engine control module (ECM) senses that some conditions are not yet in place and he wont allow it. Thats part of its programming: efficiency and protection as well. It will allow later when it senses evrythings okay. However if this blinking goes on all day, then you need to have your truck checked thoroughly, specially by scanner. Double check for leaks, too. Goodluck, and have a nice day. : )