Thanks for the replies as always.. yes air return in good shape. Unit was set on auto, yes sensor is in place, higher than one shown in picture. Mines in the center of coil located in the middle. Turbs, quick cool dump? you're talking bout defrost mode right? not sure I've heard it called that. At any rate something is not doing what its supposed to. Works great in lesser Temps.. rear unit works great no matter what the temp.
Slim, RVing 30 plus years
2015 Dynamax DX3 37 RB