If you are going to leave the gray valves open, put a block or two under the sewer hose spaced apart to create a trap to prevent the sewer gas from entering the camper. There
should not be any intake air on the roof A/C to bring the stink in. It is very possible that a gray tank may not be vented through the roof and you have a cheater vent under one of the cabinets that has gone bad. (common but only about $5 to replace) Good luck and let us know what you find, Hank
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Hank & Lynn
2007 Cougar 290RKS, E-Z Flex, 16" XPS RIBs ( SOLD
.. Gonna miss her ... looking for new 5r)
2004.5 Dodge 2500 QC, LB, 5.9HO, WestTach gauges, Ride-Rite