Water Temperature Sensor

The water temperature sensor, located at the heater core, detects coolant temperature flowing through heater core. It is a negative type thermistor; resistance will increase with lower temperatures, and decrease with higher temperatures.
The sensor will compare temperature settings with the INCAR air temperature or the ambient air temperature for electromotive heating control.
CHECK

Fig 1: Water Temperature Sensor Characteristics Table
Courtesy of HYUNDAI MOTOR CO.
Electromotive heating control
At AUTO mode, discharge mode FLOOR or B/L, if coolant temperature is low, it will perform electromotive heating control to prevent cold air discharge toward the passenger legs.
1. Operation control
  - Discharge mode FLOOR or B/L at AUTO control
  - Coolant temperature is low
2. System operation
  - Mode door: DEF > MIX > AUTO
  - Blower level: AUTO LO > AUTO HI
  - Intake door: Ambient air
    
    Fig 2: Testing Water Temperature Sensor
    Courtesy of HYUNDAI MOTOR CO.
    
    Fig 3: Temperature Vs. Resistance Graph
    Courtesy of HYUNDAI MOTOR CO.