
Auto defogging reduces the possibility of fogging up the inside of the windshield by automatically sensing the moisture of inside the windshield.
The auto defogging system operates when the heater or air conditioning is on.
Information
The auto defogging system may not operate normally, when the outside temperature is below 14 °F (-10 °C).

When the Auto Defogging System operates, the indicator will illuminate.
If higher level of moisture are sensed in the vehicle, the Auto Defogging System will operate in the following order:
Step 1) The A/C button will turn ON.
Step 2) The air intake control will change to Fresh mode.
Step 3) The mode will be changed to defrost to direct airflow to the windshield.
Step 4) The fan speed will be set to MAX.
If the air conditioning is off or recirculated air position is manually selected while Auto Defogging System is ON, the Auto Defogging System Indicator will blink 3 times to signal that the manual operation has been canceled.
To cancel or reset the Auto Defogging System
Press the front windshield defroster button for 3 seconds when the ignition switch is in the ON position.
When the Auto Defogging System is canceled, ADS OFF symbol will blink 3 times and the ADS OFF will be displayed on the climate control information screen.
When the Auto Defogging System is reset, ADS OFF symbol will blink 6 times without a signal.
Information
NOTICE
Do not remove the sensor cover located on the upper end of the driver side windshield glass.
Damage to system parts could occur and may not be covered by your vehicle warranty.
Defogging logic
Climate Control Additional FeaturesHyundai Elantra AD (2016-2020) Owners Manual: Limitations of the System
The LKA system may operate prematurely even if the vehicle does not depart from
the intended lane, OR, the LKA system may not warn you if the vehicle leaves the
intended lane under the following circumstances:
When the lane and road conditions are poor
It is difficult to distinguish the lan ...
Hyundai Elantra AD (2016-2020) Service Manual: Accelerator Position Sensor (APS) Repair procedures
Inspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Turn the ignition switch ON.
3.
Measure the output voltage of the APS 1 and 2 at C.T and W.O.T.
Specification : Refer to "Specification"
...