My aircon was removed when I bought the car and I couldn't be bothered to put it back in seeing as it only gets used a few times a year. I clear my screen with the heater but whenever I set the air flow to the screen the green aircon light comes on and the air source automatically switches from recirculating air to getting air from outside (orange light goes off) which is annoying when I'm sat behind a bus. So everytime I want to clear the screen I have to turn the non existent aircon off and press the button next to it to recirculate the air again. Is there a way to shop this from happening?