LG Refrigerator Error Code F3+F5

The F3+F5 code means the middle compartment defrost sensor did not reach above 16°C within 2 hours after a defrost cycle started. This points to a problem in the middle compartment defrost system, which includes the heater, temperature fuse, defrost sensor, and the heater relay on the control board. The refrigerator uses this 2-hour window as a benchmark to confirm that defrosting is occurring properly. If frost accumulates unchecked, cooling performance in that section will eventually decline.

The error itself does not indicate an immediate safety hazard, but it should not be ignored. A failed defrost system will allow frost to accumulate on the evaporator coils, which reduces cooling efficiency and can eventually block airflow entirely. In some cases, a shorted heater or failed fuse can point to an underlying electrical issue that warrants prompt attention. Addressing the error code promptly prevents food spoilage and further component damage.

A power reset may temporarily clear the code from the display, but it will not fix the underlying hardware fault. If the defrost heater, thermal fuse, or relay has failed, the defrost cycle will fail again and the code will return. A reset is only useful for ruling out a one-time control glitch. Proper diagnosis of the heater, fuse, drain, and relay should be completed to ensure the fault is genuinely resolved.

Some steps, like clearing a clogged defrost drain, are within reach for a confident DIYer. However, testing heater continuity, checking the temperature fuse, and evaluating the control board relay require a multimeter and basic electrical safety knowledge. Replacing a defrost heater or thermal fuse involves accessing internal refrigerator components, which is manageable but does require unplugging the unit and partial disassembly. If you are not comfortable working with electrical components, a qualified technician is the safer choice.

Repair costs vary depending on which component has failed. A defrost heater or thermal fuse typically costs between $15 and $60 for the part alone. If the main control board relay has failed and the board requires replacement, parts can range from $80 to $250 or more. Adding a technician's labor fee generally brings the total repair cost to somewhere between $100 and $400, depending on your location and the specific diagnosis.