My Refrigerator Compressor Is Missing the Prong Relay

How Refrigerators Work

• Refrigerators utilize the expansion of gases to keep temperatures inside the appliance cool. The refrigerant used inside refrigerators is compressed by the compressor into a liquid state then pumped into the freezer compartment. The liquid coolant passes through an expansion valve on its way to the freezer, where it expands into a gaseous state. As it expands, it pulls in the heat from the surrounding air to cool the freezer compartment. Vents inside the refrigerator then carry this cool air into the refrigerator section.

Relay Operation

• The purpose of the relay is to allow a temporary overload in the refrigerator circuit. The compressor in a refrigerator requires a good deal of power in order to start, so much power, in fact, that a device called a capacitor is used to store electricity to help the compressor motor begin a cycle. The relay also helps by turning off the electrical circuit when it detects that an overload may damage the motor. The relay connects to the compressor and the electrical system of the refrigerator through a series of prongs, or terminals, on top of the component.

Installing a New Relay

• Relay kits can be purchased from your refrigerator manufacturer or through a number of online appliance parts retailers. Specify your refrigerator make and model, as well as the specs for the relay -- printed on the side of the unit -- when ordering. Unplug the refrigerator from the outlet and pull it away from the wall so you can access the rear of the appliance. In most refrigerators, the relay is typically attached to the refrigerator body by screws. Two of the prong relays connect to the capacitor while the other connects to the refrigerator's wiring harness although this can differ from refrigerator to refrigerator.

Testing a New Relay

• Once the relay is installed, allow the refrigerator an additional half hour or so to cool down. This gives the refrigerant inside time to settle. Plug the refrigerator into the electrical outlet. Listen for the compressor fan, which tells you that the refrigerator has started. If the appliance doesn't start, look for a "reset" button on the relay and press it.