Heating and Cooling Problem

[YewDecide]

Hi, i recently purchased a used 1 series, great condition and loving the car but there is a problem with the heating and cooling system. It heats and the air con works fine, the problem is when i select any of the directional buttons, they don't do what they're supposed to. So for example, when i press the button to direct the airflow to the driver, it will go to the footwell. This is the same with all the directional buttons and seems to be random as to what happens when i make any selection. Any idea what could be the problem?