Fan blower motor keeps running in winder after the room temperature reaches the setting. Occasionally, especially in the case that the outside temperature is very low, the motor stops as expected. But most of the time, it keeps blowing air. However, it functions properly in summer, i.e., when the room temperature cools down to the setting, the motor stops.
The furnace model is Bryant 383KAV. After some online research, I checked that: (1) Fan is set to AUTO in thermostat; (2) Flame rollout limit switch HH18HA452 passes continuity check using multimeter, about 0.7 Ohms; (3) Temperature limit switch HH12ZB170 also passes continuity check using multimeter, about 0.6 Ohms; (4) LED light flashes a few times when the furnace turns on. Then it stays red all the time. I assume no error is detected.
I am confused now what could go wrong. Temperature Limit Switch HH12ZB170 has been replaced recently. Maybe I should manually disconnect each of two limit switches one by one to verify?