Understanding Your Furnace Control Board Ever wonder what that green circuit board inside your furnace actually does? Often called the "brain" of the heating system, the control board is responsible for coordinating every step of the heating process. What does it connect to? The control board acts as a central hub. It receives signals from your thermostat and distributes power to several key components, including: The Inducer Motor: Clears out any remaining combustion gases before ignition. The