The answer to 'tune-up not cooling' is that a tune-up not resolving cooling issues is often due to a more serious problem with the HVAC system. Common causes include a refrigerant leak, compressor failure, or airflow blockage. Symptoms may include warm air blowing, poor cooling performance, or the system not turning on at all.
In this case, it's best to call a professional HVAC technician to diagnose and repair the issue. Attempting a DIY fix could be unsafe and may make the problem worse. A qualified technician will be able to properly inspect the system, identify the root cause, and make the necessary repairs to restore proper cooling.