The CustomCool is a gimmicky marketing name that GE came up with for what is basically a souped-up crisper drawer in the refrigerator. The drawer has been outfitted with a system of dampers, a fan, a temperature thermistor and a heater. Depending on the function selected on the CustomCool settings in the controls at the top of the refrigerator, a combination of these components can be used to theoretically chill items quickly, thaw items or hold the drawer pan at a specific temperature.
At some point during your distinguished career as a professional appliantologist, you'll need to take apart one of these CustomCool compartments, typically to replace a fan or a damper. These things are a bugger to take apart. This video will hepya.