Why Is My AC Blowing Warm In My Car? When you push the button to turn on the AC in your Car, you expect the AC to Blow Cold Air from the vents. What does it mean when the AC Blows Warm Air? There are two sides to the AC system in your car. The first side is the power, or the control unit where you ask the AC to come on. You set the temperature control and tell the air where to blow. These temperature controls can be digital with a temperature display. Most digital controls include dual-zone climate control, or front and rear zones. They can also be analog, or use a knob that shifts the temperature along a range from cold to hot. Your vent positions are controlled the same way. They change from dash, to vent to floor depending on the position you choose. The second side of your AC system is mechanical. This part of your AC system is a sealed system. It uses refrigerant or Freon to make the air in the passenger compartment cold. Parts like the AC Compressor, AC Condenser, and Evaporator ... read more