X-2, When I turn on the a/c it blows very strong under the a/c straight down. When I close that vent it blows out of the other vents, Not nearly as strong but enough to blow out a match. The ceiling vents toward the front seem to have a much stronger air flow than the vents toward the rear. I suspect that the turns and size of the duct work slow the air speed quite a bit.
Since it looks like you purchased a pre-owned unit. Is it possible someone changed the ceiling vents for the type that can be closed or shut off?
John And Mary
2013 XLR 27 HFS
2013 CHEVROLET 2500 6.6 DURAMAX
Nights Camped 2012 (7) 2013 (33) 2014 (27) 2015 (34) 2016 (4)