Speed Queen Washer Error Code HEATING LED Flashing

The HEATING LED Flashing error on a Speed Queen washer indicates an open or shorted temperature sensor fault detected during the heating phase of a wash cycle. The machine control monitors the water temperature through a thermistor connected at connector H3. When the control reads a temperature value outside the valid operating range, specifically below 32°F (0°C) or above 212°F (100°C), it interprets this as a sensor failure rather than an actual temperature extreme. In response, the control disables the heater output to prevent any potential damage, but the cycle is allowed to complete normally. The fault is flagged at the end of the cycle via the flashing HEATING LED.

The thermistor is a resistive temperature sensor whose resistance changes predictably with temperature. The valid resistance range at connector H3 is 500 to 35,000 ohms. A reading below 500 ohms points to a short circuit in the sensor or wiring, while a reading above 35,000 ohms indicates an open circuit, usually from a broken wire, failed sensor, or a disconnected connector. Either condition pushes the reported temperature outside the acceptable window and triggers the fault. Checking resistance directly across H3 with an ohmmeter is the first step to isolate whether the fault lies in the wiring harness or in the thermistor itself.

Because the cycle completes and the error is only indicated at the end, laundry is not left sitting or damaged, but the wash water was not heated to the selected temperature. This means sanitizing cycles or temperature-sensitive wash programs may not have performed as intended. The error clears automatically when the door is opened at the end of the cycle, so it will not persist into the next cycle unless the underlying fault remains present.