If you're having problems with your HVAC system, your blower resistor is undoubtedly faulty and has to be replaced. Some of the warning signals of a malfunctioning blower motor include: (1) The blower motor amperage draw is not functioning - If you don't get air through your vents when you turn on your air conditioner or heater, it could be broken. When your blower motor malfunctions, there will be no air passage, requiring inspection or replacements. The blower motor amperage draw is minimal. Your blower motor may be broken if the airflow in your vents is poor or non-existent. A weak or damaged blower motor will not be able to deliver enough airflow to maintain a decent temperature. The fan speed is low. Another indicator of a defective blower motor is if the motor only runs at a certain speed. Most blower motors intend to operate at varying speeds to handle multiple household temperatures adequately. If your blower motor can't supply cold or warm air at its intended settings, it's a sign that it's defective. (2)