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Error code reference

LG Refrigerator Error Code dH F

Poor defrosting error; during 2 consecutive cycles the defrosting sensor did not reach over 46°F (8°C)

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Poor defrosting error; during 2 consecutive cycles the defrosting sensor did not reach over 46°F (8°C). Possible causes include temperature fuse disconnection, heater disconnection, drain jam, or poor relay for heater.

First step from the service manual

Check the door gasket for damage, then check the defrost control part (Fuse-M and defrost heater resistance).

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What dH F means on a LG refrigerator

The dH F error code on an LG refrigerator indicates a poor defrosting condition. Specifically, the refrigerator's control board has detected that during two consecutive defrost cycles, the defrost sensor temperature never climbed above 46°F (8°C). This threshold is the minimum temperature expected at the defrost sensor when the defrost heater is operating correctly. Failing to reach this level over two back-to-back cycles signals that frost or ice is not being adequately cleared from the evaporator coil.

The defrost system relies on several components working together: the defrost heater, the thermal fuse (Fuse-M), the defrost sensor, and the relay that activates the heater. If any of these components fail, the heater either does not energize at all or does not generate enough heat to raise the sensor temperature to the required level. A disconnected or open-circuit Fuse-M will cut power to the heater entirely. A failed defrost heater, confirmed by checking its resistance, will produce the same result. A faulty heater relay on the control board can also prevent the heater from receiving power even when commanded to activate.

Additional causes include a jammed or frozen drain, which allows ice to accumulate beyond normal levels and makes it harder for the heater to raise the sensor temperature, and a damaged door gasket that allows warm, humid air to enter the refrigerator compartment continuously, accelerating ice buildup. Diagnostics should begin with a visual inspection of the door gasket for tears or gaps, followed by resistance testing of the Fuse-M and the defrost heater to confirm continuity and proper values.

Source: manufacturer service documentation.

Common causes of dH F

  1. 01

    Failed Defrost Heater

    Part replacement

    The defrost heater element may be open-circuit, meaning it draws no current and generates no heat. Check the heater's resistance with a multimeter; an open reading or infinite resistance confirms the heater needs replacement.

  2. 02

    Blown Thermal Fuse (Fuse-M)

    Part replacement

    The Fuse-M is a one-shot thermal cutoff that disconnects the heater circuit if temperatures exceed a safe limit. If it has blown, the heater will not receive power regardless of relay or control board status. Test for continuity across the fuse to confirm.

  3. 03

    Faulty Heater Relay

    Part replacement

    The relay responsible for switching power to the defrost heater can fail in the open position, preventing the heater from energizing even when the control board sends the correct signal. This requires inspection of the control board or relay assembly.

  4. 04

    Damaged Door Gasket

    Part replacement

    A torn, compressed, or warped door gasket allows warm, moist air to continuously enter the refrigerator, accelerating frost accumulation on the evaporator coil well beyond what the defrost cycle can handle. Inspect the gasket around the full perimeter of the door for gaps or deformation.

  5. 05

    Clogged or Frozen Defrost Drain

    Wiring / connection

    If the defrost drain is jammed with ice or debris, meltwater backs up and refreezes around the evaporator, creating an excessive ice load that the heater cannot adequately address within the defrost cycle duration.

See the test procedure for each cause

Frequently asked questions about dH F

What does dH F mean on a LG refrigerator?
The dH F code means the refrigerator detected a poor defrost condition. During two consecutive defrost cycles, the defrost sensor never reached the required threshold of 46°F (8°C), indicating the defrost heater is not functioning properly. Common causes include a blown thermal fuse, a failed heater, a bad heater relay, or a damaged door gasket allowing excessive frost buildup.
Can I fix the dH F error myself, or do I need a technician?
Some steps, like inspecting and replacing a damaged door gasket or clearing a frozen defrost drain, are manageable for a knowledgeable DIYer. Testing the defrost heater resistance and the Fuse-M continuity requires a multimeter and comfort working around refrigerator electrical components. Replacing the control board relay or the heater itself is more involved and may warrant a qualified technician.
Will resetting the refrigerator clear the dH F error code?
A power reset may temporarily clear the code from the display, but it will not resolve the underlying problem. Because the error is triggered after two consecutive failed defrost cycles, the code will return as soon as the defrost system fails again. The root cause must be diagnosed and repaired to permanently clear the error.
Is it safe to keep using the refrigerator while it shows dH F?
Continued use with an active dH F error is not recommended. Frost will continue to accumulate on the evaporator coil, progressively reducing cooling performance and eventually blocking airflow entirely. This can lead to food spoilage in both the freezer and fresh food compartments. Addressing the error promptly prevents further damage to the appliance.
How much does it cost to repair the dH F error on an LG refrigerator?
Repair costs vary depending on which component has failed. A replacement thermal fuse or defrost heater typically ranges from $15 to $60 for the part alone. A door gasket replacement can range from $30 to $100 for the part depending on the model. If the control board needs replacement, costs can range from $100 to $300 or more for the part, plus labor if a technician is involved.

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