Blower Control Module

The blower control module is a solid state device that operates the blower motor. The blower control module outputs a voltage that varies between 0 volts (blower motor OFF) and 12 volts (maximum blower motor speed).
To determine the appropriate output voltage, the blower control module monitors a varying voltage signal (between about two and eight volts) from the HVAC programmer. The module then amplifies the signal and applies voltage directly to the blower motor. Blower control module output voltage is also monitored by the HVAC programmer.