I don't recall the year or model of AS. In any event I had a similar problem on a 27 ft Cruise Lite, SOB. I thought mold in the AC. Then thought that it was drawing in outside vent pipe air. Then I opened up the sink cabinet and stuck my nose in there. Phew!
It was the positive vent valve on the sink drain. aka Struder vent.... A couple of wacks with crescent wrench and the smell went away. They often put a positive vent valve under sinks because it is easier than running vent piping out the roof.
Most of the toilets in RVs just gravity dump into the holding tank. There isn't much pressurized black tank venting until you turn on the tank flush valves. You could do a tank flush and see if the AC draws in the stink then.
|