LG HVAC Error Code 89

Error code 89 on an LG Flex Multi LMUxxxHV outdoor unit indicates a DIP switch configuration error on the outdoor PCB. Specifically, DIP Switch 3 has been detected in the wrong position and needs to be set to OFF. The system will not operate normally until this switch is corrected. This is a configuration fault, not a component failure in most cases.

Error code 89 is a configuration fault rather than a safety-critical electrical or refrigerant issue. The system is designed to prevent operation when it detects a DIP switch mismatch, which protects the unit from running in an unsupported configuration. However, since accessing the outdoor PCB requires opening the unit cabinet, this work should be performed by a qualified HVAC technician.

If the fix requires only repositioning DIP Switch 3, the cost is limited to a service call fee, typically in the range of $75 to $150 depending on your location and technician. If the DIP switch or PCB is physically damaged and the board requires replacement, parts and labor costs can range from $300 to $700 or more. In most cases, this error is resolved quickly without any parts needed.

Locate the DIP switch bank on the outdoor unit PCB and confirm that DIP Switch 3 is in the OFF position. If it is ON, switch it to OFF and then cycle power to the outdoor unit. The error should clear once the board reads the correct switch configuration. If the error persists after correcting the switch position, the PCB itself may need further inspection.

A simple power reset will not permanently clear error code 89 because the fault is tied to the physical position of DIP Switch 3 on the outdoor PCB. Each time the unit powers on, it reads the switch position, and the error will return if Switch 3 remains in the ON position. The switch must be physically moved to OFF before the error will clear on restart.