Defrosting and defogging the windshield
Windshield Heating Do not use the position
or
while using the
air conditioner in very humid weather.
The temperature difference between the outside air and the windshield may cause fogging on the outside surface of the windshield, resulting in reduced visibility. In this case, set the mode button to
and the fan speed button to the lowest speed.
- For maximum defrosting, set the temperature knob to the far right (hot) and the fan to the highest speed.
- If you want to direct some of the warm air to the floor during defrosting or defogging, set the mode to floor-defrost.
- Before driving, clear all snow and ice from the windshield, rear window, side windows and outside mirrors.
- Clear snow and ice from the hood and the air intake at the base of the windshield to improve defroster and heater performance and reduce the risk of fogging on the inside of the windshield.

Manual Air Conditioning Control
Defrosting the Inside of the Windshield
- Set the fan speed to a position other than "0".
- Select the desired temperature.
- Set the mode to
or
. - Outside (fresh) air is automatically selected.
If outside (fresh) air is not automatically selected, press the corresponding button.

Defrosting the Outside of the Windshield
- Set the fan speed to maximum (fully to the right).
- Set the temperature to the hottest setting.
- Set the mode to
. - Outside (fresh) air is automatically selected.

Automatic air conditioning
Defrosting the Inside of the Windshield
- Select the desired fan speed.
- Select the desired temperature.
- Press the defrost button (
). - Outside (fresh) air is automatically selected.
If outside (fresh) air is not automatically selected, press the corresponding button.

Defrosting the Outside of the Windshield
- Set the fan speed to maximum (far right).
- Set the temperature to the highest setting (HI).
- Press the defrost button (
). - Outside (fresh) air is automatically selected.
Defog Logic
To reduce the risk of fogging on the inside of the windshield, air intake or air conditioning is automatically controlled based on certain conditions, such as the position
or
. To cancel or return to
the defog logic, proceed as follows.

Manual Air Conditioning Control
- Turn the ignition key to ON.
- Set the mode button to defrost (
). - Press the air intake button at least 5 times within 3 seconds.
The air intake button indicator will flash three times at 0.5-second intervals to indicate that the defog logic has been canceled or returned to its programmed state.
If the battery is discharged or disconnected, you must reset the defog logic status.

Automatic Air Conditioning
- Turn the ignition key to ON.
- Press the defrost button (
). - While holding the air conditioner (A/C) button down, press the air intake button (
) at least 5
times within 3 seconds.
The air conditioner display will flash three times at 0.5-second intervals to indicate that the defog logic has been canceled or returned to its programmed state.
If the battery is discharged or disconnected, you must reset the defog logic status.

Auto Defog (automatic air conditioning system only, if equipped)
The auto defogger reduces the risk of fogging on the inside of the windshield by automatically detecting the humidity level on the inside surface of the windshield.
The auto defog system operates when the heater or air conditioner is on.
This indicator comes on
when the auto defogger detects moisture on the inside of the windshield and starts operating.
If the air inside the cabin is more humid, the system operates at a higher level. For example, if the auto defogger does not defog the windshield at Level 1 Outside Air, it tries again at Level 2 Blow Air onto the Windshield.
Level 1: Outside air Level 2: Blow air onto the windshield Level 3: Increase air onto the windshield Level 4: Operate the air conditioner Level 5: Maximum air conditioning
If the vehicle is equipped with an automatic defroster, it operates when conditions require it. To cancel the automatic defroster, press the defroster button 4 times within 2 seconds while pressing the AUTO button. The indicator will flash 3 times, signaling that the system is canceled. To reactivate the automatic defroster, follow the steps above.
If the battery is disconnected or discharged, the defroster status is reset.
NOTICE
- If the air conditioner OFF position or manual recirculation is selected while the auto defogger is operating, the auto defogger indicator flashes 3 times to notify that the manual operation has been canceled due to the need for clear visibility.
Do not remove the sensor cover located in the upper corner of the windshield, driver's side.
You may damage system components, which is not covered by the vehicle warranty.
Test yourself
A quick Kia Optima DL3 quiz: every answer comes with an explanation and a link to the manual page.