I have a 2005 3/4 ton ctd slt model. Does anyone know if i can switch my single climate control for heat and a/c to a dual climate control model. None of the dealerships can give me a straight answer. One said i need to change out the entire heater box. Another said its not possible because it has to do with the computer. I mean is it just as simple as changing out the control panel for it or is it really not possible for my truck.