Your HVAC contactor is a heavy-duty relay that acts as a “drawbridge” for electricity, controlling the flow of power to the main components of an air conditioning or heating system, such as your compressor and fan motor. It receives a low-voltage signal from the thermostat, which energizes a magnetic coil inside the contactor. This magnetic field pulls the contacts closed, completing the higher-voltage circuit and allowing electricity to power the HVAC equipment. When the thermostat signal is re