Could it be the ambient temp sensor? (Do you notice an "E" where the outside temp displays in the gear display?)
I believe that sensor has something to do with the A/C.
You could also try an HVAC unit reset....
With the ignition off, turn the left hand rotary knob to full cold, the middle and right hand rotary knobs to Auto, press the recirc and econ buttons together and whilst still pressed, turn the ignition on. Keep them pressed until the green lights start flashing then release. When the lights stop flashing the reset is complete.