There can be several reasons why an air conditioning system fails to blow cold air, but one of the most common problems is a refrigerant leak. The refrigerant is the substance responsible for cooling the air, and if there is a leak in the system, it can cause the refrigerant level to drop, which in turn can result in the system blowing warm air.
Other potential causes of air conditioning failure include a malfunctioning compressor, a faulty thermostat, a clogged air filter, or a problem with the electrical system. It's important to have a trained technician diagnose and repair the problem to ensure that the system is functioning safely and efficiently