TSB: DEFOGGING LOGIC ? NORMAL OPERATION, DISABLING, AND ENABLING - Starting with 2010MY, all Kia vehicles, except Rio (JB), incorporate a defogging logic to prevent the interior windows from becoming excessively fogged. Depending on the specific model, the HVAC control head monitors ambient temperature and/or cabin humidity to determine which settings will best prevent the windows from fogging. If the system detects lower ambient temperature or higher cabin humidity, the defogging logic may automatically switch ON the A/C, and/or set the air intake mode to Fresh Air.
If the user changes these settings, the defogging logic will take control again after 3 to 5 minutes, depending on the procedure in this publication.