Appliance Spares
Quick answer: If your frost-free fridge is icing up at the rear freezer panel, warming up, or pooling water, the defrost system has failed — usually a faulty defrost termination thermostat or defrost sensor, occasionally the heater or timer. Test the thermostat for continuity while frozen; if it’s open, replace it. We stock genuine LG, Westinghouse, Haier and GE/Whirlpool parts with same-day Sydney dispatch.
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How a frost-free fridge defrost system works
A frost-free fridge doesn’t stop frost forming — it melts it on a cycle so you never see ice. The defrost system is a heater + a termination thermostat (or sensor) + a timer or control board working together. Every 8–12 hours the timer cuts cooling and energises a defrost heater wrapped around the evaporator coil behind the rear freezer panel. The heater melts accumulated frost, which drains away. A defrost termination thermostat is a temperature-sensitive switch clipped to the coil: it stays closed while the coil is frozen and opens once the coil reaches roughly 5–13°C, cutting the heater so it doesn’t overheat. On newer LG, Samsung and Haier fridges a defrost sensor (a thermistor) feeds the main control board instead. If any one component fails, frost builds unchecked until it blocks airflow and the fridge warms up.
Symptoms: how to tell the defrost system has failed
The classic sign is a solid sheet of ice on the rear interior panel of the freezer or fridge — that panel hides the evaporator coil. As ice chokes the fan and airflow, you’ll see knock-on symptoms. Use the table below to match what you’re seeing to the likely cause.
| Symptom | What it means | Most likely part |
|---|---|---|
| Ice slab on rear freezer/fridge panel | Frost not being melted | Termination thermostat or sensor |
| Fridge warming, freezer still cold-ish | Airflow blocked by ice | Defrost thermostat / heater |
| Buzzing or clicking fan | Fan blade hitting ice | Underlying defrost fault |
| Water pooling under crisper / on floor | Melt water not draining (or drain blocked) | Drain + defrost cycle |
| Fridge cold for a day, then warms, repeats | Partial / intermittent defrost | Sensor or timer |
If clearing all the ice (manual defrost) fixes it temporarily but it returns within days, the defrost system — not your habits — is the problem.
Safety first: 240V and mains power
The defrost heater runs on 240V mains and the evaporator area carries live wiring. Before you touch anything inside the freezer cavity or behind the rear panel, unplug the fridge at the wall — don’t rely on the door switch or thermostat dial. Pull the fridge out, switch off and remove the plug, and confirm it’s dead. The termination thermostat itself is a low-voltage-friendly switch you can test safely once disconnected, but the heater and wiring are not. If you’re not confident working near mains wiring, or your fridge is hard-wired, use a licensed technician — Australian electrical work is regulated and testing should follow AS/NZS 3760 practice. A typical defrost-part swap takes 20–40 minutes once the fridge is off and the panel is out, plus time to fully thaw any ice with a hairdryer on low.
How to test the defrost termination thermostat
You can confirm a faulty termination thermostat with a multimeter in minutes — the key is that it must be cold (frozen) to test correctly, because it’s a switch that opens when warm.
- Unplug the fridge at the wall.
- Remove the rear freezer panel to expose the evaporator coil and find the thermostat clipped near the top.
- Disconnect the two wires from the thermostat.
- Set your multimeter to continuity (or lowest ohms).
- While the thermostat is still frozen, touch the probes to its two terminals.
A healthy frozen thermostat reads continuity (near 0 ohms) — the circuit is closed, ready to feed the heater. No continuity (open / OL) while frozen = faulty thermostat; replace it. To double-check, warm it in your hand or a cup of warm water: a good one will open (lose continuity) as it warms past its rated temperature. For a sensor (thermistor) type, measure resistance and compare against the spec — it changes with temperature rather than switching on/off.
Which part to replace, and AUD cost
Most fridge defrost faults are fixed by the cheapest component — the termination thermostat or sensor — not the heater. Replace the thermostat/sensor first; only suspect the heater if it tests open and the thermostat is good, or the control board if symptoms are intermittent. Match the part to your brand and model number (on the model sticker inside the fridge).
| Part | Typical AUD | When to choose it |
|---|---|---|
| Defrost termination thermostat | $18–$45 | Frozen thermostat reads open (no continuity) |
| Defrost sensor / thermistor | $25–$55 | LG/Haier with control board, wrong resistance |
| Defrost control assembly (combo) | $35–$70 | Westinghouse/Electrolux 3-pin units |
| Defrost heater element | $45–$120 | Heater tests open, thermostat OK |
| Defrost timer / control board | $60–$200+ | Intermittent, all sensors test good |
Genuine parts cost a few dollars more than generics but match the cut-out temperature and clip exactly — critical for a switch that protects the heater. A correctly matched thermostat or sensor often outlasts the fridge itself, so the small premium pays off in years of trouble-free defrost cycles; we keep these in stock in the Sydney warehouse for same-day dispatch.
Genuine defrost parts we stock (match your model)
Find your model number on the model sticker, then match it below. Link at least one of these to your fridge and you’re ready to order — all dispatch same-day from Sydney.
| Part number | Fits | Link |
|---|---|---|
 Defrost termination thermostat — see listing | LG GN-234SQA, GN-253SQA, GN-S303GCA (72°) | |
 6615J2002A | Westinghouse N245C, N476C, RJ215M (3-pin) | |
 H0060401763D | Haier HFD462FS1, HRF516YHC, HRF516YHS, HRF516YS | |
 H0060401763D | Haier HRF565YHC, HRF565YHS, HRF700YCX | |
 37T01 / L60-18F | GE, Whirlpool, Hoover, Amana (clip-on, 3-pack) | |
 K60-P1013 | Universal push-button defrost thermostat (-4 to -24°C) |
Not sure which one? Run the Oz Part Finder with your model number.
Frequently Asked Questions
Why is my frost-free fridge icing up on the back panel?
The rear panel covers the evaporator coil. In a frost-free fridge a defrost heater should melt frost off that coil every 8–12 hours. A solid ice sheet there means the defrost cycle isn’t running — most often a failed termination thermostat or defrost sensor that’s stuck open, so the heater never fires.
How do I test a defrost termination thermostat?
Unplug the fridge, disconnect the thermostat while it’s still frozen, and check continuity with a multimeter. Frozen = should read continuity (closed). If it reads open (no continuity) while frozen, it’s faulty. As it warms, a good one opens. A sensor (thermistor) is tested by resistance against spec, not on/off.
Can I just keep manually defrosting it instead of replacing the part?
You can as a stop-gap, but if ice returns within days the defrost system has failed and will keep choking airflow and warming the fridge. Replacing a $20–$50 thermostat or sensor is cheaper than running a struggling fridge or losing food.
Is it the thermostat, the heater, or the timer?
Test the cheapest first. A termination thermostat/sensor causes most defrost faults. If that’s good and the heater reads open, replace the heater. If everything tests fine but the fault is intermittent, suspect the defrost timer or control board.
How much does a fridge defrost thermostat cost in Australia?
A defrost termination thermostat is typically $18–$45 AUD, a defrost sensor $25–$55, and a Westinghouse-style control assembly $35–$70. Heaters run $45–$120 and timers/boards $60–$200+. The thermostat is the usual fix.
Do I need an electrician to replace it?
The thermostat or sensor swap is a low-risk job once the fridge is unplugged — most people can do it in 20–40 minutes. But the defrost heater and surrounding wiring are 240V mains. If you’re working on the heater, hard-wired units, or feel unsure, use a licensed technician per AS/NZS practice.
Will any defrost thermostat fit my fridge?
No — match the part number to your brand and model, because the cut-out temperature and clip differ. An LG 6615JB2005A, Westinghouse 6615J2002A, Haier H0060401763D and GE/Whirlpool 37T01 are not interchangeable. Use your model sticker model number or the Part Finder.
Frequently asked questions
Why is my frost-free fridge icing up on the back panel?
The rear panel hides the evaporator coil, and a defrost heater should melt frost off it every 8-12 hours. A solid ice sheet there means the defrost cycle isn’t running — most often a failed defrost termination thermostat or defrost sensor stuck open, so the heater never fires.
How do I test a fridge defrost termination thermostat?
Unplug the fridge, remove the rear freezer panel, disconnect the thermostat’s two wires while it is still frozen, and check continuity with a multimeter. Frozen should read continuity (near 0 ohms); open circuit while frozen means the thermostat is faulty. A good one loses continuity as it warms.
How much does a fridge defrost thermostat cost in Australia?
A defrost termination thermostat is typically $18-$45, a defrost sensor $25-$55, and a Westinghouse-style control assembly $35-$70. Defrost heater elements run $45-$120 and timers or control boards $60-$200 plus — and the cheap thermostat or sensor is the usual fix.
How long does replacing a fridge defrost thermostat take?
A typical defrost-part swap takes 20-40 minutes once the fridge is unplugged and the rear freezer panel is out, plus time to fully thaw any ice with a hairdryer on low. Unplug at the wall first — the defrost heater and surrounding wiring run on 240V mains.
Can I just keep manually defrosting the fridge instead of replacing the part?
Only as a stop-gap. If ice returns within days of a manual defrost, the defrost system — not your habits — has failed and will keep choking airflow and warming the fridge. Replacing a $20-$50 thermostat or sensor is cheaper than running a struggling fridge or losing food.
Will any defrost thermostat fit my fridge?
No — the cut-out temperature and clip differ between parts, so an LG 6615JB2005A, Westinghouse 6615J2002A, Haier H0060401763D and GE/Whirlpool 37T01 are not interchangeable. Match the part number to your brand and the model number on your fridge’s model sticker, or use the Part Finder.
Related guides
- Find your exact part with the Oz Part Finder
- Fridge not cold but freezer working — airflow & evaporator fan diagnosis
- Water pooling under the crisper — fridge drain and defrost troubleshooting
Ready to fix it?
Match your fridge’s model number to the right defrost thermostat or sensor above, or run the Oz Part Finder and we’ll point you to the exact genuine part — dispatched same-day from our Sydney warehouse.
