Please check if the push buttons for the fan speed and the heated/cooled seats at the bottom of unit work. Please see circled part of image.
Those buttons are from the factory - it communicated through the factory AC system without the unit. If the AC circuit board behind is installed correctly, these buttons should work. If they do not work, please check the image below where there are two ribbon cables holding the two circuit boards together. Verify that these two ribbon cables are installed correctly.
There are only one side of the ribbon cables that make connection - the other side is just plastic. Please make sure they are facing the right way.