Samsung Air Conditioner Error Code 37

Error code 37 on a Samsung air conditioner indicates a heatsink temperature sensor fault on the IPM (Intelligent Power Module). The IPM is a critical component in the inverter drive circuit, responsible for converting DC power to variable-frequency AC to control the compressor speed. Embedded within or directly mounted to the IPM is a thermistor that monitors heatsink temperature to protect the module from thermal damage. When the control board detects an abnormal signal from this sensor, whether an open circuit, short circuit, or out-of-range resistance reading, it triggers error code 37 and shuts down operation to prevent component damage.

The primary diagnostic focus for this error is PIN #24 and PIN #25 of the IPM module, which carry the heatsink temperature sensor signal. Solder joints at these pins are a common failure point, particularly in units exposed to repeated thermal cycling, vibration, or humidity. Cracked solder joints can create intermittent or total loss of the sensor signal, while a short circuit between the pins or to adjacent circuitry will produce an out-of-range reading that triggers the fault. Physical inspection of the PCB under magnification is the recommended starting point.

Beyond solder joint failures, a failed thermistor within the IPM assembly or damage to the signal wiring between the sensor and the control board can produce the same fault. Because the IPM integrates power switching transistors, gate drivers, and protection circuitry into a single module, internal sensor failure typically requires full IPM replacement. Technicians should measure sensor resistance at the relevant pins before condemning the module to confirm whether the fault is in the sensor itself or in the surrounding circuit.