Refrigerator: Frost buildup in freezer

If frost is building up in the freezer, check first for a break in the door gasket that could be letting in warm, moist air. If the gasket seems sound, a malfunction somewhere in the automatic defrost system could be the culprit. A failed defrost timer or a bad electronic control board may not initiate the automatic defrost cycle, causing excessive frost buildup on the back wall inside the freezer. A faulty defrost sensor can prevent the defrost heater from turning on the defrost cycle. See how to check the defrost sensor and other components in the defrost system in our refrigerator won't cool troubleshooting video.

refrigerator

These repairs may help solve your refrigerator problem

Replace the refrigerator defrost sensor

Replace the refrigerator defrost sensor

The refrigerator defrost sensor-also known as the defrost bi-metal termination thermostat-trips when it detects that the temperature of the evaporator is getting hot enough that it might overheat. When the defrost sensor trips, it shut off power to the defrost heater. If the defrost sensor trips because it's not working correctly, frost builds up on the evaporator fins, eventually making the refrigerator and freezer not cool well. You can use volt/ohm meter to check the defrost sensor for continuity. Replace the defrost sensor if it shows no continuity at around 0 degrees F.

How to replace a defrost sensor in a side-by-side refrigerator

If your side-by-side refrigerator isn't as cool as it should be and frost is forming in the freezer, a failed defrost sensor could be to blame. This DIY repair guide shows how to replace the defrost sensor, also called a defrost thermostat bi-metal.

Repair difficulty
Time required
 45 minutes or less
Read more
Repair the refrigerator defrost system

Repair the refrigerator defrost system

The refrigerator automatic defrost system periodically melts frost from the evaporator to improve heat exchange. During defrosting, the compressor stops, the defrost heating element turns on, and frost melts from the evaporator fins. The condensate drips to a evaporator drip tray below the evaporator and then flows through a defrost drain tube to a drain pan next to the compressor in the machine compartment. The condensate water evaporates from the drain pan before the next defrost cycled. If the defrost process fails, diagnose and repair the problem.

How to replace a defrost sensor in a side-by-side refrigerator

If your side-by-side refrigerator isn't as cool as it should be and frost is forming in the freezer, a failed defrost sensor could be to blame. This DIY repair guide shows how to replace the defrost sensor, also called a defrost thermostat bi-metal.

Repair difficulty
Time required
 45 minutes or less
Read more
How to replace a refrigerator defrost control assembly

If your Kenmore or LG refrigerator displays an Er dS error code or an Er dH error code and the freezer won't defrost, it could be the defrost control assembly failed. This DIY repair guide shows how to replace the defrost control in 8 easy-to-follow steps.

Repair difficulty
Time required
 120 minutes or less
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How to replace the defrost bi-metal thermostat in a top-freezer refrigerator

If your refrigerator isn't cooling well and frost builds up around the evaporator, the problem could be the defrost bi-metal thermostat. This DIY repair guide shows how to replace the defrost bi-metal thermostat in about 15 minutes.

Repair difficulty
Time required
 15 minutes or less
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How to replace the defrost thermistor in a top-freezer refrigerator

If your refrigerator isn't as cold as it should be, it could be a faulty defrost thermistor. This DIY repair guide shows how to replace a defrost thermistor in a top-freezer refrigerator in just 15 minutes or less.

Repair difficulty
Time required
 15 minutes or less
Read more
How to replace a refrigerator electronic control board

If the control panel lights or fans in your side-by-side or bottom-freezer refrigerator aren't coming on, it could mean the electronic control board has failed. This DIY repair guide shows how to replace a faulty refrigerator electronic control board in 7 quick steps.

Repair difficulty
Time required
 30 minutes or less
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How to replace the electronic control board in a top-freezer refrigerator

If your refrigerator won't cool at all, the electronic control board may be faulty. This DIY repair guide and video show how to easily replace the electronic control board, and it usually takes only 15 minutes or less.

Repair difficulty
Time required
 15 minutes or less
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How to replace the defrost heater in a top-freezer refrigerator

Is the freezer in your top-freezer refrigerator not as cold as it should be? The problem could be a faulty defrost heater. This DIY repair guide and video have easy-to-follow instructions on replacing the refrigerator defrost heater.

Repair difficulty
Time required
 30 minutes or less
Read more
How to replace a defrost heater in a side-by-side refrigerator

When a side-by-side refrigerator isn't cooling well and frost builds up in the freezer, the defrost heater may be at fault. This DIY repair guide with step-by-step instructions shows how to replace a failed defrost heater in a side-by-side refrigerator.

Repair difficulty
Time required
 45 minutes or less
Read more
Replace the refrigerator electronic control board

Replace the refrigerator electronic control board

The electronic control board-also called the main control board or the power control board (PCB)-controls the compressor and the defrost cycle. When it senses that the compressor must run to keep the refrigerator cool, it sends voltage to the compressor and fans. The electronic control board also receives signals from temperature sensors to monitor the temperatures inside the refrigerator and freezer. With this information, the electronic control board controls the defrost cycle. You can usually do a diagnostic test on the electronic control board to see how well it's working. The test varies by model, but the most common is the Forced Defrost test. See the tech sheet for instructions on running the diagnostics. Replace the electronic control board if it's not working correctly.

How to replace a refrigerator electronic control board

If the control panel lights or fans in your side-by-side or bottom-freezer refrigerator aren't coming on, it could mean the electronic control board has failed. This DIY repair guide shows how to replace a faulty refrigerator electronic control board in 7 quick steps.

Repair difficulty
Time required
 30 minutes or less
Read more
How to replace the electronic control board in a top-freezer refrigerator

If your refrigerator won't cool at all, the electronic control board may be faulty. This DIY repair guide and video show how to easily replace the electronic control board, and it usually takes only 15 minutes or less.

Repair difficulty
Time required
 15 minutes or less
Read more
Adjust the freezer or refrigerator door

Adjust the freezer or refrigerator door

The refrigerator or freezer doors swing on hinges that can be damaged or bent. Over time, the doors may begin to sag, allowing warm moist air into the refrigerator or freezer door that creates excessive frost that can eventually cause the drain tube to freeze. This refrigerator repair involves adjusting or repairing the hinges so that the doors work properly and stay aligned.

Replace the refrigerator defrost timer

Replace the refrigerator defrost timer

The defrost timer is an electro-mechanical device that controls the intervals between automatic defrost cycles in the refrigerator. The defrost timer motor runs and moves the control components in the device. When the control contacts in the defrost timer advance into the defrost cycle, the compressor stops and the defrost heater turns on for a specified period of time to melt frost off of the evaporator fins. This promotes more efficient exchange of heat across the evaporator. When the specified period of defrost ends, the defrost timer contacts switch back to allow normal cooling operation in the refrigerator.

You'll need to replace the defrost timer if it doesn't advance when activated.

Faulty contacts in the timer can also cause the defrost heater to either not energize at all or constantly energize. In that instance, replace the defrost timer.

Replace the refrigerator door gasket

Replace the refrigerator door gasket

The door gasket attaches to the refrigerator or freezer door panel and prevents air from entering or escaping the cabinet when the door is shut. A damaged gasket lets warm, moist air into the refrigerator when the door is closed, causing excessive frost and cooling problems. Replace the door seal if it's damaged or torn.

July 20, 2015
By Lyle Weischwill
How to replace a refrigerator door gasket

A worn or damaged refrigerator door gasket lets warm air into the refrigerator, causing frost buildup and inefficient cooling. This DIY repair guide shows how to replace the door gasket in 5 easy steps.

Repair difficulty
Time required
 30 minutes or less
Read more
Symptoms common to all refrigerators

Choose a symptom to see related refrigerator repairs.

Main causes: water valve leaking, frozen or broken defrost drain tube, overflowing drain pan, cracked water system tubing, leaking door seal
Main causes: blocked air vents, compressor problems, condenser or evaporator fan not working, control system failure, sensor problems
Main causes: leaky door gasket, defrost system failure, evaporator fan not running, dirty condenser coils, condenser fan not running
Main causes: jammed ice cubes, broken ice maker assembly, dirty water filter, kinked water line, bad water valve, freezer not cold enough
Main causes: damaged door seal, faulty defrost sensor or bi-metal thermostat, broken defrost heater, bad defrost timer or control board
Main causes: blocked vents, defrost system problems, evaporator fan failure, dirty condenser coils, bad sensors, condenser fan not working
Main causes: control board or cold control failure, broken compressor start relay, compressor motor failure, defrost timer problems
Things to do: clean condenser coils, replace the water filter, clean the interior, adjust doors to prevent air leaks, clean the drain pan
Repair guides common to all refrigerators

These step-by-step repair guides will help you safely fix what’s broken on your refrigerator.

July 20, 2015
By Lyle Weischwill
How to clean refrigerator condenser coils

Help your refrigerator run more efficiently by cleaning the condenser coils. It's easy and takes just a few minutes.

Repair difficulty
Time required
 15 minutes or less
How to replace a refrigerator temperature control board

If the temperature in your refrigerator doesn't match the temperature you set, the problem could be the temperature control board—a service technician can give you a definite diagnosis. If the board is at fault, follow these steps to replace it yourself.

Repair difficulty
Time required
 30 minutes or less
July 20, 2015
By Lyle Weischwill
How to replace a refrigerator water valve

Replace the water valve that feeds water to the ice maker and water dispenser if it no longer controls the flow of water.

Repair difficulty
Time required
 30 minutes or less
Articles and videos common to all refrigerators

Use the advice and tips in these articles and videos to get the most out of your refrigerator.

August 2, 2016
How to diagnose a faulty refrigerator water inlet valve
By Sears PartsDirect staff

Learn how to tell if the water inlet valve in your refrigerator is bad.

January 27, 2016
How to purge air from a refrigerator water dispenser video
By Sears PartsDirect staff

Follow the steps in this video to remove air from the water line connected to your refrigerator's water dispenser so the water dispenses smoothly.

January 27, 2016
How to replace a drop-down tray refrigerator water filter video
By Sears PartsDirect staff

Learn how to replace the water filter that's inside the refrigerator section of a bottom-freezer single-door refrigerator.