I just reviewed the posts for a cold cabin. I couldn't find an answer,...so help me please! We just returned from a trip from San Diego St Paul, MN. We had no heat problems going out, but as we got back into the frozen north last nite it was almost impossible to keep warm. The OAT was 20, the heat was full on in front, rear and defrost. We could feel heat coming out behind us, but when I would turn my head to the right, I could feel a nasty cold draft coming forward from the rear and hitting me on the face. Any idea how this would occur? (Also as a side note, it seems like the heating capabilities diminish when all controls are requesting full hot. There is noticebly less air coming thru the defroster, etc.). I am pulling all the floor boards up next week to make sure all is good there.