This video provides step-by-step repair instructions for replacing the PTC relay on a GE refrigerator. The PTC relay sends power to the start winding to start the compressor. If it has failed, the fridge compressor will not start but will hum, since the run winding is still energized.
All of the information for this PTC relay video is applicable to the following brands:
Tools needed: phillips head screwdriver, 1/4 inch socket, flat head screwdriver