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Bosch Freezer Runs All The Time

The part(s) or condition(s) listed below for the symptom Freezer runs all the time are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.

Most Frequent Causes for Freezer runs all the time

For the most accurate results, enter your model number.


Cause 1Room Temperature is Hot

Normal operating room temperatures for a freezer are between 60° and 95° Fahrenheit. The hotter and more humid the air is the less efficient the freezer will be, causing it to run more. If possible, keep the freezer within the recommended operating temperatures and as cool as possible.

Cause 2Sealed System Leak

On most chest freezers the evaporator coils are hidden in the walls. Some upright freezers utilize the shelves for the evaporator coils. If only one shelf of the freezer is freezing or only one section of the evaporator coil is frosting up,there may be a sealed system leak. Sealed system repairs are usually cost-prohibitive. If the sealed system is leaking, you will probably need to replace the freezer.

Cause 3Temperature Control Thermostat

The temperature control thermostat directs voltage to the compressor, evaporator fan motor, and condenser fan motor. If the temperature control thermostat is not working properly, it can cause the freezer to run continuously. To determine if the thermostat is defective, rotate the thermostat from the lowest setting to the highest setting and listen for a “click.” If you hear a click, the thermostat is not likely defective. If you do not hear a click, use a multimeter to test the thermostat for continuity. If the contacts inside the thermostat do not open, even at the lowest settings, this indicates that the thermostat is defective. If the temperature control thermostat is defective, replace it.

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Cause 4Evaporator Fan Motor

The evaporator fan motor draws air over the evaporator coils and circulates it throughout the freezer. On most refrigerators, the fan motor will not run when the door is open. Make sure that the refrigerator door is closed and the door switch is activated. If the door switch is activated but the evaporator fan motor still won’t run, replace the evaporator fan motor.

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Cause 5Condenser Fan Motor

The condenser fan motor draws air through the condenser and over the condenser coils. If the condenser fan is not running, check the fan blades for obstructions. Next, ensure that the blades spin freely. If the fan blades do not spin freely, the fan motor bearings are worn out, and the fan motor should be replaced. If no obstructions are present, and the fan blades spin freely, use a multimeter to test the fan motor for continuity. If the condenser fan motor does not have continuity, replace it.

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Cause 6Defrost Timer

The defrost timer turns on the defrost heater several times throughout the day to melt any frost that may have accumulated on the freezer evaporator coils. If the defrost heater does not turn on, frost will continue to accumulate on the evaporator coils, and the coils will eventually frost over. In order for the defrost timer to turn on the defrost heater, the defrost timer must advance into the defrost cycle. If the defrost timer is not advancing properly, the defrost heater won’t turn on. To determine if the timer is defective, slowly turn the timer with a screwdriver or by hand. Turn the timer until it clicks. When the timer clicks, the compressor and fans will shut off. If the defrost thermostat and heater are working properly, the heater will turn on. If the heater turns on, this indicates that the timer is defective and must be replaced.

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Cause 7Defrost Heater Assembly

The defrost heater turns on several times throughout the day to melt away any frost that may have accumulated on the freezer evaporator coils. If the defrost heater assembly has burned out, the evaporator coils will frost over. If the evaporator coils are frosted over, air won’t be able to pass through the coils and cool the freezer. To compensate for the decrease in cooling capacity, the freezer will run continuously in an attempt to keep the freezer cold. If you suspect that the defrost heater isn’t working, first check the evaporator coils. If the coils are plugged with frost, the defrost system is not working properly. Next, use a multimeter to test the defrost heater for continuity. If the defrost heater does not have continuity, replace it.

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Cause 8Defrost Thermostat

The defrost heater turns on several times throughout the day to melt away any frost that may have accumulated on the freezer evaporator coils. Before the defrost heater turns on, the defrost thermostat must sense that the evaporator coils are cold enough. If the coils are cold enough, the defrost thermostat will allow the defrost heater to turn on. (Usually, the temperature of the coils must be below 30 degrees Fahrenheit.) If the thermostat is defective, the defrost heater won’t turn on, causing the evaporator coils to frost over. To determine if the defrost thermostat is at fault, use a multimeter to test the thermostat for continuity. If the defrost thermostat does not have continuity, replace it.

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Cause 9Door Not Fully Closing

Check to see that the doors are closing properly. If a door bin or food item is keeping the door open slightly the freezzer may not cool properly, which can cause the freezer to run all the time.

Cause 10Condenser Coils are Dirty

If the condenser coils are located within the freezer walls, the coils do not require cleaning. However, if the condenser coils can be readily accessed from behind or under the unit, you should clean them every 6-12 months. If the condenser coils are dirty, they won’t be able to dissipate heat effectively, greatly reducing the cooling capacity of the freezer. If the condenser coils are dirty or have not been cleaned in a while, clean them.

Cause 11Main Control Board

Control boards are often misdiagnosed—before replacing the control board, first check more commonly defective parts. If you have determined that all of the other components are working properly, replace the main control board.

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Cause 12Sealed System Leak

If the freezer only freezes the top shelf, there may be a sealed system leak in one of the shelves. Sealed system repairs are usually cost-prohibitive. If the sealed system is leaking, you will probably need to replace the freezer.

Cause 13Closing Cam

A freezer door closing cam allows the door to rest in place in the open position and to close securely on its own when the door is swung shut. A damaged closing cam can prevent the door from closing properly, allowing warm air to enter the freezer which will result in the compressor running continuously in an attempt to maintain an appropriately cold air temperature. Inspect the closing cam for damage and replace if necessary.

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Cause 14Thermistor

The thermistor monitors the freezer temperature and sends the temperature reading to the control board. The control board regulates power to the compressor and evaporator fan based on the thermistor readings. If both the condenser fan motor and evaporator fan motor are running, you should test it with a multimeter. The thermistor resistance should change in conjunction with the freezer temperature. If the thermistor resistance does not change, it's possible the component is sending an inaccurate temperature reading to the control board resulting in the freezer running all the time. A new thermistor should be installed to solve the problem.

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Cause 15Control Board

If the freezer runs all the time a relay on the control board may be shorted, sending constant power to the compressor. Control boards are often misdiagnosed—before replacing the control board, first check more commonly defective parts. If you have determined that all of the other components are working properly, replace the main control board.

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Cause 16User Control and Display Board

A short in the user control and display board could be responsible for the freezer running all the time, although this is rarely the case. Control boards are often misdiagnosed—before replacing the user control and display board, make sure you check more commonly defective parts. If you determine that all of the other components are working properly, replace the user control and display board.

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Cause 17Door Gasket

A twisted or worn gasket can allow cool air to escape the freezer and warm air to enter resulting in the freezer running all the time. Inspect the door gasket for kinks, wists, or damage. You can use a hair dryer to try smoothing out the kinks. If the door gasket is damaged it will need to be replaced.

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