What we found out last week and then discovered others have had the same problem as we were experiencing was odors form your sewer vents coming back inside the RV. This is do to the fact your sewer vents sit so close to the AC unit that it is bringing the smell right back inside. The suggestion to stop this problem is to put on new vents. We chose to have Camping World install 2 Cyclone Vents while the Kodiak was there. These will take care of that smell!