mypros+
Error code reference

LG Refrigerator Error Code F dH

Poor defrosting

LG codesLG refrigerator codes
Avg. service call
$285
National average. Trip fee plus diagnostic plus labor. Before parts.
MyPros+ 3-day pass
$9.95
Same diagnostic steps, on your phone. Start now.
You keep in your pocket
~$275
Even before you buy the part.
Skip the service call. Fix it yourself.
Full procedure unlocks instantly.
Get Started

What the F dH error code actually means

Your LG refrigerator is showing an F dH error because it tried to defrost itself but could not get warm enough inside the freezer section to complete the process. This usually means a safety fuse, a heating element, or a temperature sensor has failed and needs to be checked. Until this is fixed, frost will continue to build up on the cooling coils, which will eventually reduce how well the refrigerator cools.

Diagnostic procedure

The full F dH procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check the door gasket for damage, then check the defrost control part (Fuse-M resistance and defrost sensor resistance).
Unlock with pass
Unlock with pass
Unlock with pass
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
Unlock F dH procedure $9.95

Or subscribe: $29/month for unlimited access to all codes plus Max AI diagnostics.

Most common causes of F dH

Ranked by how often they cause this code
  1. 1Blown thermal fuse (Fuse-M)
  2. 2Defrost heater disconnection or failure
  3. 3Failed defrost sensor
  4. 4Clogged or frozen defrost drain
  5. 5Damaged door gasket

Most DIYers save hundreds by diagnosing before ordering parts.

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass

Questions people ask about F dH

What does F dH mean on a LG refrigerator?
The F dH code means the refrigerator detected a defrost heater error. Specifically, the defrost cycle ran for a full hour but the evaporator sensor temperature never exceeded 46°F (8°C), which is the threshold that confirms successful defrosting. The fault is typically caused by a blown thermal fuse, a failed heater element, a bad defrost sensor, a clogged drain, or a faulty heater relay on the control board.
Is it safe to keep using the refrigerator when F dH is displayed?
Continuing to use the refrigerator with an active F dH error is not recommended for extended periods. Without a functioning defrost cycle, frost will accumulate on the evaporator coils and eventually block airflow entirely, causing the refrigerator and freezer sections to lose cooling capacity. Food safety can become a concern if temperatures rise enough.
How much does it cost to repair an F dH error on an LG refrigerator?
Repair costs vary depending on which component has failed. Replacement parts such as a thermal fuse or defrost sensor are generally in the range of $10 to $50, while a defrost heater assembly can cost $30 to $100 or more. If a technician is needed for diagnosis and labor, total repair costs typically range from $100 to $300 depending on your location and the parts required.
Can I fix the F dH error myself, or do I need a technician?
Some causes, like a frozen defrost drain or a damaged door gasket, can be addressed by a knowledgeable DIYer with basic tools. However, diagnosing and replacing internal components like the thermal fuse, defrost heater, or defrost sensor requires a multimeter and comfort working around refrigerator wiring. If you are not familiar with appliance diagnostics, a licensed technician is the safer option.
Will resetting the refrigerator clear the F dH error code?
Unplugging the refrigerator or resetting the control board may temporarily clear the displayed code, but the underlying fault will remain. The error will return once the next defrost cycle runs and the same failure condition is detected. The root cause, whether a failed fuse, heater, or sensor, must be diagnosed and corrected for the code to stay cleared.

Related LG refrigerator error codes

All LG refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass