I had a sewer smell and found that the anti siphon valve located in the sink island (Left corner) was only screwed on by one thread on to the vent stack. I tightened it up, but I'm going to replace it with a better valve.
2012 Dodge 3500, SLT Big Horn,CC,DRW,Cummins HO, EB, 4x4, 3:73, Retrax Pro, Q20, TST507, Garmin RV760, Sleek 4g
2014 Cedar Creek, 36CKTS, 640w Solar, TriStar MPPT 60, Magnum 2000w, PI EMS, WiFi Ranger Elite, Sleek 4g, Wingard DTV Traveler
Retired Army in 1995, and now retired in 2016