Our spare 25+ year old Kitchenaid refrigerator (side-by-side model) refused to produce cold air. I could hear mechanical sounds and things "clicking", but the temps kept raising. This specific unit only had cooling coils in the freezer, and some ducts that route cold air into the fridge.
I emptied the refrigerator completely, removed the ice cube bin and shelves, and left it unplugged for two days with the doors open. Once everything was dry, I plugged the unit back in -- within 8-10 hours, the unit was cold again. Lights worked, and fans in the freezer and back of unit worked. However... once the compressor turned off, it never came back on. This told me that the root cause lies with components that control when to turn off/on the cold flowing into the coils.
I looked up my model on PartSelect website, and looked through their "likely to fail" list for my model. The defrost thermostat and defrost timer were at the top of the list, and symptoms made sense. Those two parts arrived within a week. The defrost timer was easy to install -- unplug old, plug in new. The defrost thermostat involved cutting existing wires, stripping a small section of sheathing, and attaching the wires to the new part with crimp caps and electrical tape. The electrical tape was there to cover the exposed area of the crimp cap and bundle the wires together. (I used 3M's "Super 33+".) Finally, reattach the harness to the socket, and attach the other plugs and grounding clamp.
After re-attaching the rest of the required components, I plugged the unit back in. After about 24 hours, it had gone through at least one cycle and was appropriately cold. After letting it churn for another couple days and watching it closely, I felt confident that the problem had been fixed.
** Side Notes **
Definitely use caution around the fins on the coil. For my unit, the harness plug is directly above the fins, and required some effort to safely remove while not slicing up my hands. Extra long screwdrivers and patience helps a lot. Put a wedge behind the wheels of the refrigerator so that it doesn't back away from you while you work. And, of course, do all this while it is unplugged.
** For the PartSelect Website Maintainers **
If possible, please provide some better guidance on where to place the lead coming off the defrost timer. The Youtube video was nice, but some clarity on which pole/spade to attach it to (and where to find that info, besides "consult your manual") would help many people.
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