Sonata GL V6-3.0L (1997)
Coolant Temperature Sensor / Switch HVAC: Testing and Inspection
1. Immerse thermo sensor in engine coolant.
2. Using a stove, heating engine coolant, check that electrical current continues as shown
below 115° C Continuity
over 115° C No continuity
COLD ENGINE LOCK OUT (CELO) SENSOR
The CELO sensor is wired to the electronic blend door actuator and attached to the heater core inlet tube under the actuator mounting bracket with a
spring tension clip.
The two leads to the clip start in the wire and connector assembly which feeds into the electronically controlled blend door actuator. It automatically
prevents blowing out of cold air at high flow rate when the outside air temperature is low with the engine not warmed up
This control is provided only when the blower switch is in the AUTO range.
Until the engine coolant temperature reaches approximately 50° C (122° F) or the desired temperature becomes equal or more than inside temperature
+3° C, cold air will not blow inside and fan speed is at low mode.
In the MANUAL mode, the speed is in accordance with the range setting and the fan control at low warm coolant temperature does not work.
CHECKING THE OPERATION OF COLD ENGINE LOCK OUT (CELO)
1. Immerse the cello sensor in water.
2. Using a stove, heating the water measure the resistance between terminal 1 and terminal 2.
