Thermador Refrigerator Error Code F3

F3 indicates an open circuit in the sensor wiring between the temperature sensor and the control board connector J1. The control board detected no valid resistance signal from the sensor for 16 or more consecutive seconds. This means the electrical path to the sensor is broken, either due to a disconnected wire, a failed sensor, or a damaged harness.

Operating the refrigerator with an active F3 code is not recommended, because the control board cannot reliably monitor temperatures without a functioning sensor. This could result in inadequate cooling or temperature swings that affect food safety. The issue should be diagnosed and repaired promptly.

Resetting the refrigerator by cycling power may temporarily clear the F3 code, but the error will return if the underlying fault in the sensor circuit has not been corrected. The control board is designed to detect the open circuit condition within 16 seconds of startup, so the code will reappear quickly if the sensor or wiring is still faulty. A proper repair of the open circuit is required for the code to stay cleared.

A knowledgeable DIYer can begin by checking all wiring connections at the J1 connector on the control board and testing the sensor resistance with a multimeter. If the sensor reads approximately 1000 ohms at room temperature and all connections are secure, a technician may be needed to trace the harness or evaluate the control board. Replacing a sensor is a straightforward repair if you can confirm that is the failed component.

Repair costs vary depending on the root cause. If only a connector needs to be reseated or cleaned, the cost may be limited to a service call fee, typically in the range of $75 to $150. Replacing the temperature sensor usually adds $50 to $150 in parts. If the control board is at fault, parts and labor costs can range from $300 to $600 or more.