'generally' it will be either where the shore power cord enters the coach, maybe in the outside service bay, OR it will be inside the coach, maybe under the bed/frame, or possibly in a service cabinet. It is simply a 'box' that both the Shore and Gen outputs come into, on one side, and the output to the Main Panel on the other.
Do you have an issue that you might think is the ATS?
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada.... formerly Georgia, then NorthCarolina, now Alabama : )