LG HVAC Error Code 65

Error code 65 indicates a fault with the inverter heat sink temperature sensor in the outdoor unit. The control board has detected a signal from the thermistor that is outside acceptable parameters, indicating the sensor may be open, shorted, or disconnected. The system shuts down to protect the inverter from potential damage. LG Tech Support should be contacted first because the repair path depends heavily on which model you have.

No. The system shuts down when code 65 is triggered specifically to prevent inverter damage from unmonitored heat sink temperatures. Attempting to override or repeatedly reset the system to keep it running risks destroying the inverter module, which is one of the most expensive components in the outdoor unit. The system should remain off until the fault is properly diagnosed and repaired.

A power reset may temporarily clear the code and allow the system to restart, but if the underlying sensor or wiring fault is still present, the error will return quickly. Repeated resets without addressing the root cause do not fix the problem and can mask the fault during a service call. Code 65 should be treated as a persistent fault requiring proper diagnosis rather than a nuisance code that resolves on its own.

This repair is not straightforward for most homeowners. On some older LG outdoor units, the heat sink thermistor is a discrete replaceable component that a skilled technician can test and swap. On newer models, the sensor is integrated into the inverter assembly, making field replacement of just the sensor impossible. Contacting LG Tech Support before any disassembly is strongly recommended to confirm what is serviceable on your specific unit.

Repair cost depends on what component has actually failed. If the issue is a wiring connector or a discrete replaceable thermistor, costs are typically lower, generally in the range of $150 to $400 including labor. If the fault requires replacement of the full inverter assembly, costs can range from $600 to well over $1,500 depending on the model and inverter pricing. Getting confirmation from LG Tech Support on the correct part architecture before committing to a repair path can help avoid unnecessary expenses.