If your car's AC is not cooling down and the temperature is stuck at 28°C (82.4°F) even though you have set it to 24°C (75.2°F), there could be several reasons for this issue. Here are some common possibilities:
Faulty Temperature Sensor: The AC system in your car relies on temperature sensors to detect the cabin temperature and adjust the cooling accordingly. If the temperature sensor is faulty or not reading the correct temperature, it may prevent the AC from cooling properly.
Refrigerant Leak: A refrigerant leak can lead to reduced cooling performance in the AC system. If there's not enough refrigerant in the system, it won't be able to cool the air to the desired temperature.
AC Compressor Issues: The AC compressor is responsible for compressing the refrigerant and circulating it through the system. If the compressor is malfunctioning or not working at its full capacity, the AC won't cool effectively.
Airflow Problems: If there are restrictions in the airflow, such as clogged air filters or blocked vents, the cooled air may not reach the cabin properly, leading to reduced cooling performance.
Electrical Issues: Problems with the electrical components, such as relays or switches, can also affect the AC system's functionality.
The "RT" you mentioned is not clear to me without additional context. It's possible that it might refer to a specific setting or mode in your car's AC system. If you could provide more information or clarify the "RT" term, I might be able to give you a more specific answer.
Regardless, since car AC systems can be complex and potentially involve refrigerant handling, it's best to have the issue diagnosed and repaired by a qualified automotive technician or an AC specialist. They have the necessary tools and knowledge to identify the problem and perform the appropriate repairs to get your AC working correctly again. Trying to troubleshoot or fix the AC issue without proper expertise could lead to further complications or damage to the system.