Suggest to repair at workshop. The usual keypoints and procedure of repair are:
1. Check if the radiator fan belt is broken due to aging, replace if it is faulty.
2. Check the wiring around radiator fan if it is loosen or open circuit, replace if it is faulty.
3. Check if the radiator fan is faulty, replace if it is.
4. Use scan tool to check the thermostat, repair or replace if it is faulty.