The answer to 'tune-up freezing up' is that a frozen air conditioning unit is often caused by a problem with the refrigerant levels, airflow, or compressor. Common symptoms include ice buildup on the coils, reduced cooling, and the unit shutting off. Solutions can include cleaning the coils, checking the refrigerant charge, and addressing any airflow restrictions.
In many cases, a frozen AC unit requires professional diagnosis and repair. Attempting DIY repairs on a refrigerant system can be dangerous and may void the warranty. It's best to call an HVAC technician to properly inspect, diagnose, and fix the issue.