Do-It-Yourself Story

When coils in the freezer were completely frosted over, using online exploded diagrams for my refrigerator model, I narrowed down to three suspect parts: defrost thermostat, defrost timer, or defrost heating element (or a combination of these). At first, was considering just replacing all 3, but decided to try thermostat only first. When I removed the old thermostat, it had clearly blown, so I was confident replacing just that would suffice. It did. Running smooth for ~2 weeks now, coils are not frosting over. Another $2500 appliance expense averted!