There are a various reasons why a air conditioner is not blowing cold air. Check the air filter and clean it if necessary. A clogged air filter will cause the unit to run innefficiently. Make sure that there is no ice in the unit. If the air conditioner has iced up, it will not blow cold air. Check the freon and have refrigerant added if the unit is low. Low freon will cause the unit to blow warm air.