If your auto-car air conditioning system blowing hot air instead of cool, the auto-car refrigerant gas may have leaked out, you may have a clogged condenser, or the air conditioner's blend door may be stuck. Whatever the cause of the problem, the auto-car air conditioning system needs immediate car care service. Turn the system off. You can cool the auto-car vehicle interior by putting the ventilation control in the "vent" position and/or opening the automotive car windows.