Kia Troubleshooting Questions? Ask a Mechanic
Do you have a test light or volt meter so we can do some testing?Is this a manual system?
This may be a problem with the blower resistor is what I am thinking. If it's burned out on the lower fan speed but not the upper speeds it's the likely issue in my opinion. I am sure the switch could be bad as well, but usually it's the resistor on the manual climate control.