The Most Common Causes
Ranked by how often this kind of fault turns out to be each one. A list isn’t a diagnosis — that takes someone looking at your specific machine — but it’s worth knowing what’s on the menu before anyone quotes you.
Faulty Thermistor or Temperature Sensor
A small sensor reports fresh-food temperature to the control board. When it drifts and reads warmer than reality, the board keeps calling for cold that isn’t needed. Everything gradually overcools. Inexpensive part, and the symptom is unmistakable once it’s tested rather than guessed.
Stuck or Failed Damper
The damper is the door between freezer and fridge that meters cold air across. Stuck open, freezer-temperature air pours in continuously. Some are mechanical, some motorised; both jam, often from ice forming around the flap.
Items Placed Directly In Front of a Vent
Not a fault, but a real and common cause. The air coming out of the fresh-food vent is well below freezing. Anything parked directly in that stream — a carton of milk, a bag of greens — freezes while the rest of the fridge sits at a normal temperature.
Temperature Set Too Low
Worth ruling out early. A fridge should sit around 3–4°C. Dials get knocked, digital controls get changed by a curious child, and some models drop into a colder mode after a power interruption without anyone touching them.
Failed Control Board
The board runs the cooling logic. When outputs fail, the compressor or damper can run continuously regardless of what the sensors report. Less common than a thermistor, and considerably more expensive, which is exactly why it should be diagnosed rather than assumed.
Damaged Door Seal Causing a Run-On Cycle
A leaking gasket lets humid room air in. The fridge responds by running far longer than it should, which overcools the areas nearest the vents while the door end stays warm. The giveaway is frost building somewhere it shouldn’t.
Before You Call
Worth ruling out first. If one of these is the answer you’ve saved yourself a service call, and if none of them are, the diagnosis starts from a better place:
- Check the setting first. Aim for roughly 3–4°C in the fresh-food compartment. If someone recently reorganised the kitchen or the power blinked, start here.
- Note exactly where things freeze. Only near the back wall or under a vent suggests placement and airflow. Everywhere, including the door shelves, suggests sensing or control.
- Move food away from the vents and wait a day. If the freezing stops, you’ve found it and it costs nothing.
- Put a thermometer on a middle shelf. Displays are frequently optimistic. An actual reading is the difference between a real fault and a misread display.
- Check the door seal with a sheet of paper. Close it on a sheet and pull. If it slides out with no resistance anywhere along the run, the gasket isn’t sealing.
In Calgary
One local pattern worth mentioning: garage and basement fridges. Plenty of homes in Mahogany, Auburn Bay and Seton and across the surrounding towns keep a second fridge somewhere unheated. Standard fridges are designed to run in a heated room, and when the surrounding air drops toward freezing the thermostat can misread the situation entirely — producing frozen fresh food, a warm freezer, or both. If the fridge that’s freezing food lives in a cold space, that’s the first thing to investigate, and it isn’t necessarily a fault.
Why a Real Diagnosis Matters
Several causes on the list above produce an identical symptom, and they sit at very different price points. That’s the whole argument for testing rather than guessing — a wrong part fitted confidently still leaves you with a broken appliance and a smaller bank balance.
What a Proper Diagnosis Does
- Tests the sensor instead of replacing the board. A thermistor and a control board produce overlapping symptoms and sit at opposite ends of the price range. Testing takes minutes; guessing wrong is expensive.
- Checks the damper physically. Ice around a damper flap explains everything and points at a defrost problem behind it. Replacing the damper without finding the ice source means it returns.
- Confirms it’s a fault at all. Sometimes the answer is that a milk carton is sitting in the cold air stream. That’s a free answer and you should get it.
- Rules out the expensive causes properly. On a fridge past a certain age, a failed board changes the repair-or-replace conversation. That deserves a real diagnosis, not a shrug.
What the Repair Typically Costs
Kodiak quotes labour as a flat rate per repair type, after diagnosis but before any work begins. Parts are quoted separately on your invoice. Typical labour ranges:
Fridge Overcooling Repairs
Standard repair: Thermistor, damper assembly, door gasket and thermostat work falls in the $220–350 range for labour. Parts quoted separately.
Control boards are their own conversation. Board prices vary enormously by brand and model, and on an older fridge the honest recommendation is sometimes replacement. We’ll give you the numbers and a straight opinion before you commit.
Service-call fee: $119, applied toward the repair if you proceed.
Your firm quote comes from your tech after diagnosis, before any work begins. You approve before we touch anything. Full pricing details.
Related Reading
- Fridge Not Cooling — The opposite symptom — and a different set of causes.
- Fridge Repair Calgary — Main fridge service page.
- Is It Worth Repairing? — How age, part cost and fault type decide whether a repair makes sense.
Ready When You Are
Frozen produce is annoying; a fridge running continuously is also quietly costing you money. Worth diagnosing properly. Kodiak launches in Calgary October 2026 — join the waitlist for day-one priority booking.