FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Coolant Temperature Sensor / Switch HVAC: Testing and Inspection

WATER TEMPERATURE SENSOR
1. 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.
2. The sensor will compare temperature settings with the INCAR air temperature or the ambient air temperature for motive heating control.




CHECK
3. Electromotive neating control
At AUTO mode, discharge mode FLOOR or B/L, if coolant temperature is low, it will perform motive 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