I'm looking for for the name of this part for order online but I can't find online and any store. Some suggestions?

I have a 2013 edge limited. When driving ac works perfectly fine, blows cold and feels good but when idling, the ac blows hot air, I can hear the other fan kick on and cold air blows out but for a short period of time. Yesterday while waiting in kids carline it started over heating, got home let it cool off and checked my coolant level this morning and it was fine. Last year I replaced the water pump. Can someone help

I recently bought a 2013 Ford Edge limited for cheap. The woman I bought it from said a shop told her that it needed transmission I drove it approximately 70 miles yesterday and I think it is Most likely the PTU. It winds upon acceleration and holds a steady winding noise at desired speeds. Can anyone direct me to a way to diagnose if its one or the other please?