Thermistors and Cabin Filters
The cabin air filter is responsible for preventing dust, dirt, pollen, bacteria, and exhaust gases from entering the cabin of the vehicle. If clogged with dust and debris, cabin air will not properly transfer air to the blower motor then to the evaporator. Without cabin air passing across the evaporator, the thermistor, an electrical resistor, will interpret low temperatures at the evaporator as a signal that the evaporator is at maximum cooling capacity. The thermistor communicates information that turns the A/C system on/off to keep the evaporator as cold as possible without freezing. Because the cabin air filter is clogged and there is no velocity of air, the thermistor would send an electrical signal to turn off the A/C system although the cabin has not been properly cooled.
Before beginning an A/C repair, it is best practice to check the cabin air filter. Replacing the cabin air filter is typically an inexpensive maintenance and can help extend the efficiency and life of the A/C system.
Before beginning an A/C repair, it is best practice to check the cabin air filter. Replacing the cabin air filter is typically an inexpensive maintenance and can help extend the efficiency and life of the A/C system.
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gpd_tech_tip_145-service_precaution-thermistor-cabin_air_filter-evaporator.pdf |