On my 2015 27fb I have the same strong sewer smell in the closet. (no smell under the closet) This happens when we travel down the hwy with sewer in the tanks. It is especially bad when the fantastic fans covers are open for cabin ventilation in hot weather. The dealer has looked at it twice and still have the problem.... may have to make the 1000 mile trek to Jackson Center. I don't think its from the grey tank... thinking it from the black tank. Next test is to drain just the grey tank and tow to check for smell. Any ideas?
"Ferdara" Mark and Michael Broussard-Hubbard
Aluminum pulling Aluminum 2015 F-150 FX4 Platinum, 3.5L V-6, 6.5 bed, 3.31 ratio, Roadmaster Active Suspension ~ 2015 Airstream Custom Ordered 27fb International Serenity - Lafayette Louisiana