What Is A Refrigerator Defrost Timer?

A refrigerator timer, a.k.a. a defrost timer, is a device that regulates the amount of frost inside a refrigerator. Refrigerators are designed to defrost automatically on a time-based system (Defrost Timer). The defrost timer will automatically turn on to melt frost before it has a chance to build up. Without a defrost timer, frost could build up inside your fridge. If your fridge starts to accumulate frost, doesn’t cool properly, or is too cold, you could have a failure in one of the three components that make up the refrigerator’s defrost system: the timer, heater, and bi-metal thermostat.

Most modern refrigerators use a timer to stabilize frost levels and prevent ice buildup. When the coils inside your refrigerator get too cold, the defrost timer tells the heater to turn on and melt away excess ice. This stabilizes the temperature and frost level inside the fridge.

The defrost timer is typically located behind the control panel, under the bottom front grate, or at the back of the fridge behind the freezer grill. It automatically switches between defrost and regular cooling modes to either melt frost or cool the fridge’s inside.

When the refrigerator timer is in defrost mode, the refrigerator stops cooling and starts melting frost by activating its heater. When the timer returns to cooling mode, the heater turns off, and the fridge cools again.

Switching between heating and cooling keeps the temperature inside your fridge within a safe range and prevents ice buildup.

History Of A Refrigerator Defrost Timer

Historically, refrigerators were periodically defrosted manually. The refrigerator was unplugged, emptied, and allowed to defrost thoroughly. It was then dried out and plugged back in to get cool again. Finally, the food was put back in the fridge. This was a time-consuming and potentially dangerous practice because food could be left out for hours while the fridge defrosted, where it could spoil.

Over time, manufacturers developed the “frost-free” refrigerator, which used a defrost timer to automatically regulate the amount of frost inside the fridge. Using a defrost timer eliminates the need to manually defrost a refrigerator because it warms and cools the fridge by itself.

Where Is The Defrost Timer Located?

A refrigerator’s defrost time is located on the backside of the fridge behind the freezer grill, behind the control panel, or behind the front kickplate at the bottom of the unit. To get to it, you’ll have to remove the rear grill, the control panel, or the kickplate.

How Do I Know If The Defrost Timer Is Bad?

Like any part of an appliance, a refrigerator’s defrost timer can eventually go bad. If you think your timer is going bad, test it with a multitester. Unplug the fridge and remove the device. It’s located behind the control panel, under the front lower kickplate, or behind the rear freezer grate. Once it’s removed, attach one probe of your multitester to the common terminal (often marked “C” or “3”) and the other to one of the three remaining terminals. Do this one at a time to get a reading from each terminal. The readings for one to two terminals should be “zero,” while the other one or two should read “infinity.”

The readings should reverse when you manually adjust the timer to the other setting. If the readings don’t follow this pattern, the timer is bad and needs to be replaced.

Signed of a bad defrost timer are:

Refrigerator is too warm.
Freezer won’t defrost.
Freezer is too warm.
Frost builds up on the freezer coils.

Before replacing your defrost timer, I recommend resetting it. To reset the timer, use a screwdriver and turn it counterclockwise until it clicks or won’t turn anymore. Then check the fridge in about half an hour to see if the reset helped. If the reset didn’t help, your timer is probably malfunctioning.

What Happens If The Defrost Timer Stops Working?

A refrigerator’s defrost timer initiates a defrost cycle that warms the fridge and prevents ice buildup. If the timer stops working, a defrost cycle won’t be started, and frost will build up inside the refrigerator. Eventually, the frost could lead to ice, and your fridge could malfunction. A functioning defrost timer is an essential part of a refrigerator. It prevents frost buildup and helps regulate the temperature inside the fridge.