If it is like mine, when in A/C mode, fan speed is determined by the temperature difference between measured temp and the set temp. I don't recall the specific numbers, but try lowering the set point to at least 8 degrees lower than measured temp and wait a few min. Then the blower should cycle to high speed.
Remember in Auto mode, the fan cycles off with the compressor. As an alternative, you can change the fan to Manual mode and then you can set whatever speed you like. But the fan will run 100% of the time.
Texas Baptist Men-Retiree Builders member since '01
13 Silverado 3500HD D/A, 2wd CCSB srw, custom RKI bed
11 Cruiser CF32MK