No, Darnit, The Light Doesn't Go Out When I Close The Door!

Try to access a parts book.

Sometimes the key to figuring out a puzzling design is to look at the entire part. Your local RV service center should be a starting point. Once access is made use a 12 volt test light and if power is showing on both sides of the switch disconnect one wire or a harness and check either for continuity or power on both sides of a disconnected switch.