So I'm having an interesting problem with my new houses A/C. I turned on the A/C last night at the control unit and I found that once the A/ C kicks on the control units LCD shuts off and none of the controls work. The A/C just cranks away getting the house as cold as possible. The only way to turn it off is to pull the panel off and push it back into the 7 prong socket and turn off the A/C within the first 5 seconds before the LCD shuts off. Now from what I remember my home inspector told me the internal and external coils are older while my furnace is one of those 4 year old 93% efficiency gas furnaces. Btw, if the heat is on this problem never occurs. Could this just be a control problem? This doesn't happen if lets say I set it at cool to 78 degrees and the current temp is 74 degrees. It only happens once the set temp is lower than the current temp. Basically when the A/C kicks on.