[sk5t]

Quite a few newer cars don't draw a distinction between running the heater or A/C: you just set a desired temperature, and the climate control system figures out what to do based on internal and exterior conditions. (Whether this is a good approach for a car's climate control system is another question, however.)

[ceejayoz]

I doubt the Tesla does that. If it did, Musk would've said something along the lines of "setting the cabin temp to 50 kicked on the A/C".