A contactor is an electromechanical switch used to control the flow of high-voltage power to the compressor and outdoor fan motor. When the thermostat calls for cooling, a low-voltage signal energizes a coil within the contactor, pulling down a set of silver-plated points to complete the circuit. This component is a common point of failure in Mobile Home AC Condensers due to "pitting" or insects getting caught between the contacts. If you hear a loud humming but the unit won't start, the contactor may be stuck or burned out. You can find replacement heavy-duty electrical components in our Parts collection to get your system running again. Many ACIq systems use enclosed contactors to protect against environmental debris and extend the life of the electrical system. Regular inspection of the contact points can prevent a total system shutdown during the peak of summer. It is an essential link between your home’s control logic and the high-power cooling machinery.