there is a way to lock them and take over with driver command and no it is not in defrost mode. when the system is on press and hold the auto button for a few seconds. it will take over and adjust the blower speed and blend door settings as this happens the arrows will lock and you now have driver command. then set your desired blower speed, temperature, and position this will take it out of auto. it will stay locked to drivers command until a passenger adjusts their side, even with ignition cycles. hope you enjoy.