Hyundai Elantra HD: Manual climate control system
1. Turn the ignition switch to the ON position.
2. Turn the mode selection knob to the defrost position ().
3. Push the air intake control button ()
at least 5 times within 3 seconds.
The indicator light in the air intake control button will blink 3 times with 0.5 second of interval. It indicates that the defogging logic is canceled or returned to the programmed status.
If the battery has been discharged or disconnected, it is reset to the defog logic status.