Appliance Spares
Quick answer: If your Fisher & Paykel fridge runs but cools unevenly (freezer fine while the fridge stays warm, or temperatures swinging and over-freezing) a failed temperature sensor is feeding the control board wrong readings. The Temperature Sensor Kit Assembly 855203P ($29.95) is the cheapest first part to try, with same-day dispatch from our Sydney warehouse.
Last updated June 2026
A Fisher & Paykel fridge that hums away normally but can’t hold an even temperature is one of the most common faults we help Australians sort out. The compressor runs, the light comes on, the freezer might even be rock-solid, yet the fresh-food compartment sits warm, or the temperature swings up and down and over-freezes your veggies. Nine times out of ten this isn’t a dead fridge. It’s a sensor lying to the brain. The temperature sensor (thermistor) tells the control board how cold each compartment is. When it drifts or fails, the board makes the wrong call and cools too little, too much, or in the wrong spot. The 855203P Temperature Sensor Kit is a cheap, fast-moving part, and it’s the smart first thing to swap before you spend money on bigger components.
Why is my Fisher & Paykel fridge not cooling evenly?
Uneven cooling means the fridge is trying. There’s airflow and the compressor is cycling, but the result is wrong. The patterns we see most on Fisher & Paykel fridges are:
- Freezer fine, fridge warm. The freezer holds temperature but the fresh-food side never gets cold enough. The board thinks the fridge is colder than it really is and stops cooling it early.
- Temperature swings and over-freezing. Milk freezes on the top shelf one day, then everything’s lukewarm the next. The board is chasing bad readings up and down.
- The compressor runs constantly or barely at all. A sensor reading too warm makes the fridge run non-stop. One reading too cold makes it shut off too soon.
All three come back to the same cause: the temperature sensor (thermistor) is sending the control board an inaccurate signal. A thermistor changes its electrical resistance as the temperature changes, and the board reads that resistance as a temperature. When the sensor degrades, the maths is wrong and so is the cooling.
Be honest with yourself before you buy, though. Uneven cooling can also come from a faulty control board, a stuck damper (the flap that meters cold air into the fresh-food compartment), or a failing evaporator fan. The sensor is just the cheapest and most likely first part to try, which is why we start there. If the sensor checks out and the fault stays, you’ve spent under $30 ruling it out and narrowed things down to one of those three pricier components.
It helps to know how Fisher & Paykel fridges manage cooling, because it explains why one sensor causes such different symptoms. The control board doesn’t measure temperature directly. It goes entirely off what the thermistors report. A sensor reading too warm makes the board over-cool that zone (your over-freezing). One reading too cold makes it under-cool (your warm fridge). Because the same board runs both compartments off these readings, a drifting sensor can throw the whole cabinet out of balance, which is why the symptoms can look so different from one day to the next.
4 checks, in order (cheapest first)
Work through these before you replace anything. The first three are free.
- Door seal closing properly, fridge not over-packed. Run your hand around the door seal for a draught and check it isn’t torn or folded. Make sure shelves and drawers aren’t jammed so full that the door can’t shut or air can’t move. A door that doesn’t seal, or a crammed cabinet, mimics a cooling fault exactly, and it costs nothing to fix.
- Internal vents not blocked by food. Cold air enters each compartment through vents, usually at the back or top. A casserole dish or a stack of containers pushed against a vent starves one zone of cold air while another gets too much. Pull food back a few centimetres and leave clear gaps.
- Coils and fan clear. Check the condenser coils (rear or underneath) for dust and pet hair, and make sure the internal fan isn’t blocked by frost or packaging. Dirty coils and a blocked fan both cause poor, uneven cooling.
- The temperature sensor (thermistor). If the door seals, the vents are clear and the coils and fan are clean but cooling is still uneven or swinging, the 855203P temperature sensor is the prime suspect. If you’re confident with a multimeter, test the sensor’s resistance. A healthy thermistor reads a specific, stable resistance at a given temperature and changes smoothly as it warms or cools. A reading that’s open-circuit, dead-short, or wildly out of range confirms a failed sensor.
The part that usually fixes it
If the free checks come up clean, the 855203P Temperature Sensor Kit Assembly is the part to fit. It’s a genuine Fisher & Paykel sensor kit, it dispatches same-day from our Sydney warehouse, and at $29.95 it’s a lot cheaper than guessing at a control board.
| Part number | Fits these models | Genuine/Compatible | Price | Buy |
|---|---|---|---|---|
| 855203P | Fisher & Paykel fridge/freezer models using the temperature sensor kit assembly | Genuine | $29.95 |
Not certain the 855203P matches your exact model? Don’t guess. Fridge sensor kits vary across Fisher & Paykel’s range. Run your model number through the part finder quiz or browse the full fridge parts category and we’ll confirm fit before you buy.
When to call a tech vs DIY
A thermistor swap is one of the more DIY-friendly fridge repairs. It’s a low-voltage sensor, not a sealed refrigeration part, so there’s no gas or special licensing involved in fitting the kit. If you’re comfortable unplugging the fridge, removing a trim cover and unclipping a connector, and you’ve confirmed the sensor with a multimeter resistance check, the 855203P is a sensible self-fix.
Call a technician if you’ve replaced the sensor and the uneven cooling continues (that points to the control board, damper or evaporator fan), if the compartment isn’t cooling at all rather than unevenly (possible compressor or sealed-system fault, which is licensed work), or if you’re not confident identifying and testing the sensor. Fitting a $29.95 sensor first is always the smart move. It either fixes the fault outright or rules the cheapest part out so a tech can go straight to the real culprit.
Frequently asked questions
How much is the Fisher & Paykel temperature sensor kit 855203P?
The 855203P Temperature Sensor Kit Assembly is $29.95. It dispatches same-day from our Sydney warehouse.
Is the 855203P a genuine Fisher & Paykel part?
Yes. The 855203P is a genuine Fisher & Paykel fridge/freezer temperature sensor kit assembly.
Will the 855203P fit my Fisher & Paykel fridge model?
It fits Fisher & Paykel fridge/freezer models that use this temperature sensor kit assembly, but sensor kits vary across the range. Check your model number with our part finder quiz before ordering so we can confirm the exact match.
How do I know it’s the sensor and not the control board?
You don’t know for certain without testing, but the sensor is the cheapest part to rule out. If your door seals, the vents are clear and the coils and fan are clean, the thermistor is the prime suspect. A multimeter resistance check confirms it: a failed sensor reads open, shorted, or far out of range. If a new sensor doesn’t fix it, the fault is more likely the control board, damper or fan.
Can I replace the temperature sensor myself?
Usually yes. It’s a low-voltage sensor, not a sealed refrigeration part, so there’s no gas or licensing involved. Unplug the fridge first, remove the trim covering the sensor, unclip the old one and fit the 855203P kit. If you’re not confident testing or accessing it, a technician can do it quickly.
How long does delivery take?
We dispatch the 855203P same-day from our Sydney warehouse on orders placed before the daily cut-off, so most Australian metro customers receive it within a couple of business days.
Uneven cooling on a Fisher & Paykel fridge is rarely the disaster it feels like. Most often it’s a cheap sensor feeding the control board the wrong numbers. Work the free checks first, confirm the thermistor with a multimeter if you can, then fit the genuine 855203P kit and let the board read the truth again. Order it below for same-day Sydney dispatch, or browse the full fridge parts range if you need anything else.
