This has been my main complaint so far with the truck, I've not been able to take mine off of MAX + LO temp since getting it. If I use anything other than just the front vent setting, the front vents might as well not be on.
In other words, if I turn on ventilated seats, very little airflow comes from the main vents even at max speed. Same if I use feet + main, main has no airflow. If the temp is any higher than LO, it honestly feels like heat, even at 65, which is only one tick up from LO.
Granted it's been a hot summer, I feel like I should have control over more than just the fan speed.