Motor home ac problem

Motorhomes have inherent vacuum leaks in transit. That means they will suck in outside air. You have a major source of outside air gaps somewhere in your motorhome. You need to open up cabinet doors and cabinet floor panels to find the source. A usual source is the area where the fresh water/Black Water tank system is located. They sometimes do not seal off the holes cut thru the floors for the plumbing. Another source if rear engine Diesel is the back wall area and the hot engine heat is drawn in thru the various gaps that were not correctly sealed. One way to determine where you have the gaps is to find a Service Center that has a smoke machine to fill the interior with pressurized smoke and then find the areas where the smoke comes out. Doug