Also check the electric, water, and sewer chase above the door side cargo door. The chase is covered by carpeted cover on the cargo bay ceiling above the door. I had a sewer type smell coming from the bedroom dresser that only occurred when we ran the bathroom vent fan.
Took me a year to track it down, it was coming from the washing machine drain pipe. I located a hole in the upper portion of the drain by feeling it with my fingers. I believe the hole was was drilled to install wires above the drain pipe. I covered the hole with heavy A/C metal duct tape. That cured the odor problem for me.