Wattsup: The high temp here was about 50; cloudy all day so no solar radiant warming of the cabin. When I turned on climate control set to LO auto with no vent override, A/C defaulted to off, and climate graph showed no power draw. I have seen A/C default to 'on' in the same settings when the ambient temp was high 60s or above. So yeah, ambient temp seems to be taken into consideration in determining what LO does. But it's not like a numeric temp setting in the important detail that the heater should never be engaged in LO. If you set it to 60 and it's 20 degrees outside, the heater will run. If you turn it down one notch to LO, the heater will turn off. Same goes for HI. If it's 110 degrees in the car, HI will still turn on the heater. LO only cools, with cold outside air or a/c-chilled air; HI only heats; all numeric temp settings will heat in some settings and cool in others.