Some of the most common air conditioning problems in cars and trucks include moisture in the air conditioning system, low coolant levels, leaks or a soiled condenser. These problems may result in an air conditioning system that fails to blow cold air.
Moisture in an air conditioner will prevent the system from sufficiently cooling the inside of the car. An air conditioner works by forcing warm, moist air outside and sometimes, this moist air becomes trapped within a system. Repairs for this problem may include cleaning the air conditioner's condenser or flushing out the system.
Leaks are the most common problem associated with a vehicle's air conditioning system. Leaks will show up with an ultraviolet air conditioning leak detection kit and may be present around the fittings, on the manifolds on the compressor, or at the front seal O-rings. This type of test will not work if the compressor fails to cycle or if the system is too low.
Generally, an automotive air conditioning system goes through about 15 percent of its coolant each year. Even during colder weather, when the air conditioning system is not used, evaporation occurs. If coolant levels are low, add coolant to the system or take the car to a trained mechanic.
A dirty condenser will restrict airflow to the inside of the car, resulting in little to no cooling. Many auto parts stores sell flushing agents that may help newer condensers, but older condensers should be replaced.