2018 Malibu LT 1.5. The AC is charged. The compressor is running. The problem I’m having is the air blows cold on defrost. As soon as I switch to the dash vents I can feel the temperature go up and the vents in the rear blow extremely hot air. If I switch to floor it blows extremely hot also. All the fuses seem to be good. Any diag. Test suggestions? Any help is appreciated!