[sambam]

If your A/C's are like ours, the bedroom isn't ducted and blows from the unit only. The living room A/C has the task of cooling the whole camper through air ducts. On a 100 degree day, that can be a lot of work for the air conditioner to keep up with. I'm assuming it is running constantly and cool air is flowing through the vents. I don't know about yours, but mine can only be dampened at the unit itself. The other vents are non-adjustable. If you're not feeling air coming from your down-line vents, try closing the vents at the unit a little to see if that helps. Otherwise, since your Montana is new, there could be a blockage of some sort.