Using Multi-Meter

Remove the Water Temperature Sensor (WTS) from the intake manifold.
With the temperature sensing portion of Water Temperature Sensor (WTS) immersed in hot engine coolant, check the resistance.

Fig 1: Checking Water Temperature Sensor (Using Multi-Meter) (1 Of 2)
Courtesy of KIA MOTORS AMERICA, INC.

Fig 2: Checking Water Temperature Sensor (Using Multi-Meter) (2 Of 2)
Courtesy of KIA MOTORS AMERICA, INC.
If the resistance deviates from the standard value greatly, replace the sensor.