LG Refrigerator DH F Error Code: Defrost Heater Fault

Quick Answer

The LG DH F error code means the defrost heater circuit has an open fault. The heater (or its thermal fuse) prevents frost from permanently building up on the evaporator coils. When it fails, the coils ice over within days, airflow stops, and the refrigerator loses cooling. Test the heater first: it should read 20-50 ohms, and OL means it has burned open. Check the thermal fuse next ($5-10) before assuming the heater itself needs replacement. A blown thermal fuse is the cause in 25% of DH F cases.

LgRefrigeratorSeverity: highDifficulty: intermediate90% DIY Success

Time to Fix

30–75 min

Difficulty

intermediate

Parts Cost

$5 – $45

Tools Needed

Phillips screwdriver, Multimeter

What Does the DH F Code Mean?

The defrost heater melts frost off the evaporator coils twice daily. DH F means that heater circuit has an open fault - either the heater burned open or the thermal safety fuse protecting it blew.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Defrost heater element burned open (most common)40%

Thermal fuse blown as a one-time safety event24%

Wiring harness to heater open or connector corroded14%

Defrost timer circuit malfunction on older models12%

Control board defrost output failed10%

Symptoms You May Notice

DH F displayed on temperature panel
Thick frost visible on rear wall of freezer compartment
Refrigerator and freezer temperatures slowly rising over several days
No airflow sensation from freezer vents
Fan noise louder than usual as it strains against ice-covered evaporator

Can you reset a Lg refrigerator to clear the DH F code?

Unplug the refrigerator for 5 minutes. A power reset clears the DH F code from the display but does not repair the heater or fuse. The code will return once the control board runs its next defrost cycle check.

Tools Required for Diagnosis

Phillips screwdriverMultimeterNut driverTowels for defrost water

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Unplug the refrigerator

Unplug the refrigerator. If the freezer rear wall is covered with ice, defrost manually: leave the freezer door open with towels on the floor for 24-48 hours. Do not proceed with disassembly until all ice is melted - forcing the panel through ice can crack the evaporator cover and damage tubing.

Remove the freezer rear panel

Locate the thermal fuse

Replace the failed component (heater or fuse)

Reassemble the rear panel and plug in

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Defrost Heater Assembly6748C-0007G · $20–$45	6748C-0007G	$20 – $45
Defrost Thermal Fuse6615JB2002N · $5–$10	6615JB2002N	$5 – $10

Verify part fitment for your Lg model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

REPAIR

Estimated Cost: $25 (Parts) vs $1350 (New Machine)

Frequently Asked Questions

What does the thermal fuse do on the LG defrost heater?

The thermal fuse is a one-time safety device wired in series with the defrost heater. If the heater runs too hot or too long (due to a defrost sensor failure), the thermal fuse blows to cut power to the heater and prevent a fire. Once blown, it must be replaced - it cannot be reset.

Can I bypass the thermal fuse to test whether it is the problem?

You can temporarily bridge the fuse terminals with a jumper wire for diagnostic purposes only, but never run the refrigerator with a bypassed thermal fuse in production. The fuse exists to prevent the heater from igniting insulation or plastic. Always replace a blown fuse with the correct LG part.

Why did my thermal fuse blow in the first place?

Usually because the defrost sensor (1F code) failed, allowing the defrost heater to run too long without the sensor telling the board to stop. The thermal fuse is designed to blow in exactly this scenario. If you only replace the fuse without also fixing a bad defrost sensor, the fuse will blow again.

How long can I leave my LG refrigerator running with DH F before food spoils?

The fridge will continue cooling normally for 2-5 days after DH F appears, depending on how quickly frost builds on the evaporator. Once frost completely covers the coils, airflow stops and temperatures rise rapidly. Act within 48 hours to avoid food loss.

Is the defrost heater spec of 20-50 ohms correct for all LG models?

The 20-50 ohm range is a general guideline. Higher wattage heaters read toward the lower end; lower wattage heaters read higher. If your heater is reading 60-80 ohms but not OL, consult your model's service manual for the exact specification before condemning the part.

Related Lg Refrigerator Error Codes

Code: HUBLG Refrigerator Error Codes: Smart Diagnosis Guide for French Door and Side-by-Side Models Code: 1FLG Refrigerator 1F Error Code: Freezer Defrost Sensor Fault

Same Fix Works on These Brands

Lg shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

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Models Known to Experience DH F Errors

This repair applies to most Lg refrigerators with this error code. Common model numbers include:

LRMVS3006S, LRFXS2503S, LRFXC2416S, LRMGS2806S, LSXS26366S

Last verified for technical accuracy on March 14, 2026