How to Set the KIA Optima (2004–2008) Air Conditioning to Use Internal Airflow by Default on Engine Start

1. Set the Fan Speed to Zero
Turn off the A/C fan completely by adjusting the fan speed dial to the 0 position. This is important as the sequence won't work if the fan is active.

2. Press the Defroster Button
Tap the defrost button (usually marked with a windshield icon and upward arrows). This step helps the system enter configuration mode.

3. Press the Internal/External Air Flow Button Five Times
Find the Internal/External Air Flow button (usually marked with a car and an arrow looping inside or passing through it).
Press it five times. You should see the indicator light start blinking and then stay solid. This confirms the system has accepted the input.

4. Press the Button Again to Set Internal Airflow
After the light stays solid, press the button once more to confirm that internal airflow is selected.

5. Test It Out
Turn off the engine, then turn it back on to see if the setting sticks.
If the internal airflow is still selected, congratulations—you've successfully set it as the default.