Heat/ac not blowing

[Alicia_09]

I have a 2018 expedition max limited and for several months the ac/heat will blow hard sometimes but other times it barely blows or not at all. It doesn’t seem to be affected by the outside temperature, it just happens randomly. At first it was just the front ac and only after the vehicle had been on for a while but now it is happening almost every time we are in it and the back ac/heat will blow sometimes and then sometimes will not work at all. I changed the air filter a couple months ago.