A fault with the blower motor or blower relay would most likely produce which symptom?

A fault with the blower motor or blower relay would most likely produce which symptom?

• A. Blower motor not running while cooling is called for
• B. Condenser fan continues to run
• C. Compressor runs continuously
• D. Thermostat stuck open

Answer: (A)

The thing being tested is how the indoor blower motor and its relay control airflow. When the thermostat calls for cooling, it energizes the blower relay to run the indoor blower motor, circulating air over the evaporator coil. If the blower motor or its relay is faulty, the blower won’t start, so no air is pushed through the ducts even though cooling is requested. That’s why the symptom is “the blower motor not running when cooling is called for.” The other possibilities don’t fit as well because they involve the outdoor unit or the thermostat’s cooling call itself rather than the indoor blower: the condenser fan running continuously is an outdoor-side issue; a thermostat stuck open would prevent a cooling call altogether; and the compressor running continuously points to issues with the outdoor unit's control or refrigerant cycling, not a failure of the indoor blower.

The thing being tested is how the indoor blower motor and its relay control airflow. When the thermostat calls for cooling, it energizes the blower relay to run the indoor blower motor, circulating air over the evaporator coil. If the blower motor or its relay is faulty, the blower won’t start, so no air is pushed through the ducts even though cooling is requested. That’s why the symptom is “the blower motor not running when cooling is called for.”

The other possibilities don’t fit as well because they involve the outdoor unit or the thermostat’s cooling call itself rather than the indoor blower: the condenser fan running continuously is an outdoor-side issue; a thermostat stuck open would prevent a cooling call altogether; and the compressor running continuously points to issues with the outdoor unit's control or refrigerant cycling, not a failure of the indoor blower.