What Is a Thermostat?

In modern appliances, thermostat usually refers to the temperature sensor — a probe that reports the actual temperature inside an oven cavity or refrigerator compartment back to the control board, which then cycles the heating element or compressor to hold the target temperature. It's less a standalone thermostat in the old mechanical sense and more one input the control board relies on.

A drifting or failed sensor causes an oven to run hotter or colder than the display shows, or a refrigerator to cycle unevenly — a common, often misdiagnosed cause of food that consistently over- or under-cooks despite a temperature setting that hasn't changed.

Frequently Asked Questions

Why does my oven run hotter or colder than the temperature I set?

The most common cause is a drifting temperature sensor reporting an inaccurate reading to the control board, which then over- or under-heats trying to hit a target it thinks is correct. It's frequently misdiagnosed because the display still shows the number you set.

Can an oven's temperature sensor be tested before replacing it?

Yes — a technician checks its resistance at room temperature against the manufacturer's expected value. A reading well outside that range confirms the sensor, rather than the control board, is the problem.