Whirlpool Fridge Freezer Fan Noise and Warm Fridge in East Lake Landing, Palm Harbor: A Bad Defrost Thermistor

We’d worked for this client in the East Lake Landing neighborhood of Palm Harbor before, and this time it was urgent. Their Whirlpool French door refrigerator (model WRF560SEHZ, made in 2018) had a freezer fan making a really nasty noise, and the fridge section up top was getting warmer than it should.

A defrost problem, right away

Those two symptoms together point to the defrost system. Frost was already built up on the back panel of the freezer.

With the panel off, the evaporator coil was covered in ice, and it had built up right around the fan. With the coil iced over, cold air can’t get through to the fridge section, so it starts to warm up.

Testing each part

To find out which part had failed, we took the freezer apart and checked each piece of the defrost system on its own, the heater, the thermistor, and the wiring around them. The connections matter too. The heater line carries a fair amount of current, and sometimes a part is fine but its contacts have burned, so we look at those as well.

The defrost heater read about 30 ohms, which is normal. The thermistor read around 1 kilohm, and at that temperature it should read much higher. The thermistor is a little sensor clipped to the coil, and the control board uses it to tell how cold the coil is. With that low reading, the board thought the freezer was warm and never started a defrost. So the ice just kept building.

Defrosted and fixed

We had a new thermistor with us, so we fully defrosted the coil and replaced it right there on the same visit.

The defrost cycle works again, and the refrigerator is back to normal.

If your freezer fan starts grinding or scraping and the fridge feels warmer, don’t wait on it. Ice is usually building up, and the sooner the defrost is fixed, the less there is to melt. More on our refrigerator repairs.