When checking your air con, you should first do a visual inspection. Look for signs of wear and tear and make sure all parts are properly connected and secured. Check the external unit and fan to ensure they are free from debris or dust. Inspect the indoor coils for any damage or dirt buildup. Check the filters for any clogs or blockages which can affect the airflow. Make sure to change or clean the filters regularly. With that said, it’s always best to acquire the services of an expert vehicle technician.