Our '05 Landmark Grand Canyon has a odor problem which seems to be coming from the 2nd AC (Duo Therm heat pump) which is mounted in the ceiling of the bedroom. So far here in AZ this summer I've been using only the AC in the bedroom, as I wish to delay the use of the other as I don't like the noise. There seems to be an odor coming from the bedroom AC which is not pleasant; its hard to describe, perhaps something like a smelly sink drain. Last evening it got so bad that I finally turned it off and the smell went away. I've been cleaning the filters and went up on roof this a.m., took the cover off the unit and it looks and smells fine. Anyone have any ideas.