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 pulse width modulated voltage signal 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.
The blower control module is located near the blower motor and is mounted to the side the HVAC module.