Appliance Spares
Quick answer: A fridge that is not defrosting shows up as a sheet of ice on the freezer back wall, a fridge section that slowly warms while the freezer stays cold, and a fan that gets louder as the ice closes in. On a frost-free fridge four parts run the defrost cycle: the defrost heater, the defrost thermostat (bi-metal), the defrost sensor or thermal fuse, and the defrost timer or control board. Switch the fridge off for 24 hours with the doors open to clear the ice, then test the four parts in that order. Each is a plug-in part listed for your model sticker below.
WESTINGHOUSE FRIDGE DEFROST HEATER ELEMENT 500W LARGE 600mm WIDE p/n5130601 0922In stock · Sydney warehouseView part- Samsung Fridge Defrost Heater DA47-00247C SRS582HDW,SRS583HDP, SRS585HDSS 0624In stock · Sydney warehouseView part
- WESTINGHOUSE 1433633 FRIDGE DEFROST THERMOSTAT RS623S,RS625S,RS642S,RS643S, 0620In stock · Sydney warehouseView part
- Samsung Fridge Bimetal Thermostat DA47-10160J SR366NTS SR367NW SR368NTSIn stock · Sydney warehouseView part
- Universal RF151 Fridge Defrost Thermo Bi-metal Thermostat suits all 0613In stock · Sydney warehouseView part
- Samsung Fridge Freezer Defrost & Temperature Sensor DA32-00006W,DA32-00024FIn stock · Sydney warehouseView part
- Haier Fridge Freezer Defrost sensor H0060401763D HRF565YHC,HRF565YHS, HRF700YCXIn stock · Sydney warehouseView part
- Hisense Fridge Freezer Defrost Sensor K1418409 HR6BMFF320S HR6BMFF520S 3575In stock · Sydney warehouseView part
- Hisense Fridge Defrost Temperature Fuse K1418420,HR6TFF272S,HR6TFF350S,HR6TFF350In stock · Sydney warehouseView part
Fit check: the model number on your sticker must appear in the listing title — the badge on the front is not enough. All fridge and freezer parts · Not listed? Send us the model number and we match it before you pay.
Last updated November 2026
How to tell a defrost fault from a cooling fault
A frost-free fridge makes ice on purpose. The evaporator behind the freezer panel frosts up while the compressor runs, and a few times a day a heater melts that frost so the water runs to a tray on the compressor. When any part of that cycle stops, the frost builds into a solid sheet, blocks the air channel to the fridge section, and the fridge warms while the freezer still reads cold.
So the symptoms of a refrigerator not defrosting are specific, and they are different from a fridge that is simply not cooling:
- Thick frost or a flat sheet of ice on the back wall inside the freezer, not just around the door.
- The fridge section creeps above 5°C over a week or two while the freezer stays around −18°C.
- The evaporator fan gets louder, then rattles or scrapes as the blades touch ice, then goes quiet when it jams.
- A manual defrost (power off, doors open, overnight) fixes everything for two to six weeks, then the ice is back.
If the freezer is also warm and there is no ice at all, the problem is cooling, not defrost. Work through the fridge checklist instead. If the ice sits only around the door frame, it is the door seal letting moist air in, not the defrost system.
First: clear the ice properly
Every test below needs a thawed evaporator. Food into an esky, fridge off at the wall, both doors propped open, towels down, a full 24 hours. Never chip at the ice with anything sharp, because the evaporator tubing behind it carries the refrigerant and one nick is the end of the fridge.
While it thaws, find the model sticker on a side wall inside the fridge section, on the ceiling, or just inside the door frame. Write the full code down, because the defrost parts are matched by that code and not by the brand on the door.
The four parts, in the order they fail
Pull the freezer back panel off once the ice is gone, usually four screws and a couple of clips. Test in this order, from the most common failure to the least.
| # | Part | What it does | How it fails | How to test it |
|---|---|---|---|---|
| 1 | Defrost heater | A glass tube or metal sheath element clipped under or through the evaporator fins. Melts the frost each cycle. | The element burns open. No heat, so the frost builds every day. | Unplug the two heater wires. A multimeter on ohms should read a few tens to a few hundred ohms. Open circuit or infinity means a dead heater. |
| 2 | Defrost thermostat (bi-metal) | A small disc clipped to the evaporator pipe. Closes when cold so the heater can run, opens once the fins are warm. | The disc sticks open. The timer calls for defrost but the heater never gets power. | Test it cold. Straight out of the thawed freezer it should read closed (near zero ohms). Warm it in your hand for a minute and it should open. Stuck open when cold is a failed thermostat. |
| 3 | Defrost sensor or thermal fuse | Electronic fridges use a sensor that tells the board the fin temperature; many add a one-shot thermal fuse that cuts the heater if it overheats. | The sensor drifts and the board never starts a cycle. The fuse blows after one overheat and stays open. | Sensor: resistance changes as it warms in your hand; a fixed reading means it has failed. Fuse: should read closed; open means replace it, and check the heater is not shorted before you do. |
| 4 | Defrost timer or control board | Older fridges use a mechanical timer in the control housing or behind the kick plate; newer ones use the main board. | The timer motor stops, so the fridge never leaves the cooling cycle. | Turn the timer screw slowly clockwise until it clicks. The compressor should stop and the heater should warm within minutes. If nothing happens with a good heater and thermostat, the timer has failed. |
Two rules of thumb. A dead heater often has a tired thermostat beside it, so replace both and save a second strip-down. And if the thermal fuse has blown, check the heater resistance before fitting the new fuse, or a shorted heater blows it again on the first cycle.
Match the part to your model sticker
Each row names the part and the models on the sticker that the listing covers. The code on your sticker must appear in the listing title before you order. Universal heaters and bi-metal thermostats are listed by length, wattage and clip style, so measure the old one before you choose.
| Part | Brand | Models on your sticker | Part listed for it |
|---|---|---|---|
 Defrost heater | Westinghouse | Large frost-free models, 600 mm wide element (check the listing) | Westinghouse fridge defrost heater, large |
 Defrost heater | Samsung | SRS582HDW, SRS583HDP, SRS585HDSS | Samsung fridge defrost heater |
 Defrost heater with sensor and fuse | Samsung | Aluminium heater models (check the listing) | Samsung defrost heater kit with sensor and fuse |
 Defrost heater | Haier | HSBS555AS, HSBS555AW | Haier fridge defrost heater |
 Defrost heater | Fisher & Paykel | Fridge and freezer models (check the listing) | Fisher & Paykel fridge defrost heater |
 Defrost thermostat | Westinghouse | RS623S, RS625S, RS642S, RS643S | Westinghouse fridge defrost thermostat |
 Bi-metal thermostat | Samsung | SR366NTS, SR367NW, SR368NTS | Samsung fridge bi-metal defrost thermostat |
 Defrost thermostat | LG | GN-234CW, GN-234SQA, GN-253CW and listed models | LG fridge defrost termination thermostat |
 Bi-metal thermostat | Universal | Any brand, clip-on disc (measure the old one) | Universal fridge defrost bi-metal thermostat |
 Defrost and temperature sensor | Samsung | Electronic models (check the listing) | Samsung fridge defrost and temperature sensor |
 Defrost sensor | Haier | HRF565YHC, HRF565YHS, HRF700YCX | Haier fridge freezer defrost sensor |
 Defrost sensor | Hisense | HR6BMFF320S, HR6BMFF520S | Hisense fridge freezer defrost sensor |
 Thermal fuse | Hisense | HR6TFF272S, HR6TFF350S, HR6TFF350 | Hisense fridge defrost temperature fuse |
 Thermal fuse | Westinghouse | WFB2804WA, WRB3504WA | Westinghouse fridge defrost temperature fuse |
 Defrost timer | Samsung | Mechanical-timer models (check the listing) | Samsung fridge defrost timer |
 Defrost timer | Hisense | HR6TFF460, HR6TFF203 | Hisense fridge defrost timer |
Not in the table? The brand pages list every defrost part we stock by model: Samsung defrost heaters, Samsung defrost thermostats, LG defrost thermostats, Hisense defrost thermostats and Electrolux and Westinghouse defrost thermostats.
Replacing the part
Heater. Note which way the old element sits and which clips hold it, because the new one must touch the fins the same way or the frost will melt unevenly. The wires are push-on spade terminals; if the old ones are green or crumbly, cut back to clean copper and use new insulated spades. Keep the heater wiring above the drain so it never sits in water.
Thermostat and sensor. Both clip onto the same pipe position as the old one. A bi-metal disc moved to a warmer spot opens early and the heater cuts out before the fins are clear. A sensor taped loosely reads air temperature, not pipe temperature, and the board defrosts at the wrong times.
Timer. Photograph the wiring, then match the wire colours to the old timer’s terminal numbers. Mechanical timers are not interchangeable between brands even when they look alike.
Drain. Before the panel goes back, pour a cup of warm water into the drain hole under the evaporator and check it reaches the tray on the compressor. A blocked drain refreezes under the fins and the ice is back in a fortnight even with four good parts.
When to stop and call a licensed repairer
Stop if all four parts test good and the fridge still ices up, because the fault is then the control board or a low refrigerant charge that frosts only one corner of the evaporator. Stop too if the tubing is damaged or there is a chemical smell when the panel comes off. Those are jobs for a licensed repairer.
Keeping it from coming back
- Check the freezer back wall every month in summer. A light, even frost after a heatwave is normal; a hard sheet is not.
- Do the paper test on the door seal at six points. A seal that slips lets humid air in, and that air becomes frost.
- Let hot food cool before it goes in, and clear the evaporator drain with warm water every time the panel is off.
Frequently asked questions
Why is my refrigerator not defrosting?
One of four parts has stopped: the defrost heater (most common), the defrost thermostat that lets the heater run, the sensor or thermal fuse that reports fin temperature, or the timer or board that starts the cycle. Thaw the fridge for 24 hours, take the freezer back panel off and test them in that order with a multimeter.
What causes frost build-up in the freezer?
Either moisture getting in or frost not being cleared. Moisture comes from a worn door seal, a door left ajar, or hot food. Frost not clearing is the defrost system. A sheet of ice on the back wall, with the fridge section warming, points to the defrost system; frost only around the door points to the seal.
How do I fix a refrigerator freezer frost build-up myself?
Switch off at the wall, doors open, 24 hours. Remove the freezer back panel, test the heater and bi-metal thermostat for continuity, test the sensor for a changing resistance, and advance the timer by hand. Replace the part that fails the test, clear the drain, and refit the panel. The parts are plug-in and the job is a screwdriver and a multimeter.
What should I do when the fridge is warm but the freezer is cold?
Look at the freezer back wall first. Ice there means the defrost system has failed and the air channel to the fridge is blocked. No ice means the evaporator fan or the air damper between the two sections, which are covered in the fan motor guide.
How long does a manual defrost last if I do not replace the part?
Two to six weeks in most homes, less in humid weather. Each time the ice returns the fan works harder and the fridge section spends longer above 5°C, so food spoils early. Replacing the failed part is cheaper than the food you throw out over a summer.
Is a fridge that keeps icing up worth repairing?
Yes in almost every case. All four defrost parts are in the tens of dollars to low hundreds and the strip-down is under an hour. The exceptions are a fridge past about twelve years with a failed control board, or any sign of a refrigerant leak.
Get the right part first time
Search your model number on the site, or send it through the contact page and we match it first. In-stock parts are dispatched from Sydney the day you order when it’s in by 12pm Sydney time. Oz Appliance Spares has been Australian-owned since 2009 and ships from Sydney’s Northern Beaches.
Disclaimer: this article is general information only and is provided without warranty of any kind. Appliance designs vary between models and production runs — always follow the manufacturer’s instructions, switch off and unplug the appliance before starting any work, and confirm parts against the model number on your appliance’s model sticker. Any repair is undertaken at your own risk and Oz Appliance Spares accepts no liability for injury, loss or damage arising from work performed after reading this guide, to the maximum extent permitted by law. If in doubt, use a qualified technician.
