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.
When I see this code I already know I'm pulling that rear panel and grabbing my multimeter. It's the fridge telling you the defrost cycle ran and got nothing back. Ignore it and within a week you've got a solid ice block behind that rear wall and zero airflow into the fridge section. The fresh food side starts warming up even though the freezer feels fine. Don't wait on this one.
Phillips #2 screwdriver, Multimeter with ohms and continuity settings
What Does the DH F Code Mean?
DH F is one of those codes that actually means exactly what it says. The defrost heater circuit has an open fault, and I've fixed probably a hundred of these over the years. Honestly the thermal fuse is the guilty party maybe 60% of the time, and it's a $10 part. But you can't just guess. Grab a multimeter and test both the heater and the fuse before you order anything, because ten minutes of testing saves you from buying the wrong part.
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 on the control panel display, sometimes cycling on and off as the board keeps retrying the defrost cycle and failing.
A solid sheet of frost, or a full ice block, covering the back wall of the freezer compartment when you pull the drawers out.
The fresh food section slowly warming up over 2 to 3 days while the freezer still feels somewhat cold. This confuses a lot of people into thinking the fridge is mostly fine.
Evaporator fan sounds noticeably louder or more labored than usual because it's fighting ice buildup directly on the coils.
No cold air blowing from the vents in the refrigerator section even though you can clearly hear the compressor still running.
Can you reset a Lg refrigerator to clear the DH F code?
Unplug the fridge from the wall outlet, wait a full 5 minutes for the control board to discharge completely, then plug it back in. The code should clear on its own. But I want to be straight with you. This is only a real fix if you've already replaced the bad part. If you just reset it without fixing the heater or fuse, the board will attempt another defrost cycle within 6 to 12 hours, fail again, and throw the DH F right back at you.
Tools Required for Diagnosis
Phillips #2 screwdriverMultimeter with ohms and continuity settings1/4 inch nut driver5/16 inch nut driverOld towels or rags for melt waterShallow pan or bucket for runoff
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
ComponentComponent Under Test
Expected Range20–50 ohms
ConditionIf Open (OL) or infinite, replace component.
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
Frequently Asked Questions
Why did my thermal fuse blow in the first place?
Thermal fuses don't just die randomly. Usually the defrost thermistor, the sensor that tells the fridge it's warm enough to stop the defrost cycle, gets lazy and stays closed too long. The heater just keeps running, temps climb past the safe limit, and the fuse sacrifices itself to prevent the plastic liner from melting. If you replace the fuse and it blows again within a week, you definitely need to swap that thermistor out too. I always recommend testing both at the same time to save yourself a second service call.
How long can I leave my LG running with DH F before food spoils?
Usually a few days after the code first appears, but it's a ticking clock. As that frost builds into a solid block it chokes the duct that sends cold air into the refrigerator section. The freezer might still feel somewhat cold while the fridge section climbs past 45 degrees. I've seen the fridge hit 50 while the freezer was still holding frozen goods solid. You've got maybe 48 hours before you're throwing out milk and leftovers. Fix it or at minimum do a manual defrost to buy yourself some time.
Can I still use the fridge while I wait for parts to arrive?
Yeah, you can buy yourself some time. Unplug it, let it fully defrost for a full day with towels down on the floor, then plug it back in. You'll probably get 2 to 3 days of normal cooling before the coils ice back up again. Just watch the fridge section temperature closely. Once it climbs above 45 degrees, move your dairy and meat to a cooler. I've had customers repeat this manual defrost every few days while waiting for parts to ship. It's annoying but it absolutely works as a short-term fix.
My freezer is still cold but the fridge section is warm. Is that a DH F symptom?
Almost certainly, yes. Here's what's happening. The frost builds up on the evaporator coils in the freezer area. The freezer stays cold because the compressor is still running and the freezer compartment sits right next to those coils. But the cold air that's supposed to flow through a duct into the fresh food section is completely blocked by ice. So the freezer feels totally normal while the fridge climbs to 50 degrees. Classic DH F pattern. I see this probably twice a week on LG side-by-sides and French doors.
Is DH F the same as just a plain DH error code on LG?
Similar but not identical. DH alone on an LG usually points to the defrost sensor or thermistor being the issue, and the heater itself might actually be fine. DH F specifically means the fault is in the heater circuit, either the element is open or the thermal fuse blew. Don't just swap the thermistor when you see the F at the end and call it done. Test the heater and the fuse with your multimeter first. Chasing the wrong part wastes money and leaves you back at square one.
Is this repair worth doing, or should I just replace the fridge?
If the fridge is under 12 years old, absolutely fix it. DIY parts run $25 to $60 for the heater assembly and maybe $10 to $15 for the thermal fuse. Total parts usually under $75. A tech visit runs $150 to $250 all in, mostly labor for the defrost and reassembly. Over 12 years old, do the math on what a new LG costs versus a $200 repair on a machine that might have other issues coming. Compressors, ice makers, and sealed system problems all get more likely past that mark.