The short answer
On a Thomson refrigerator this is usually a control board or thermistor giving the wrong picture rather than a sealed-system or compressor fault. The first checks below cost nothing and need no panel off; the one at the bottom of the list is a service call.
What you actually observe
- The cabinet is warm while the unit is plainly running — You can hear it working. The air inside is not cold and has not been for a day or more.
- The freezer still holds but the fresh-food side does not — Cold is being made and is not being moved, which points at airflow rather than at the sealed system.
- NEAR MISS: only the ice maker has stopped — Cooling is fine. That is an ice or water-supply fault, not a cooling one.
Causes, most likely first on this build
- A control board or thermistor giving the wrong picture — The unit acts correctly on a wrong reading. It stops calling for cooling, or calls for it endlessly, and nothing mechanical is wrong. It leads on Thomson: an electronically controlled unit built light puts the board in front of the mechanics.
- A stalled defrost cycle icing the evaporator — The evaporator frosts over, the air path closes, and the cabinet warms while the compressor keeps running. Second, because a cabinet cut-out leaves a compact unit almost no air gap, so anything that restricts flow bites here first.
- A condenser coil blanketed in dust — The coil sheds the heat the system removes. Covered, it cannot, and the unit runs constantly without pulling the cabinet down. Third: a restricted vent turns a normal cycle into an overheating one.
- A sealed-system or compressor fault — The system has lost charge or the compressor is no longer pumping. The unit runs and never gets cold anywhere. Last, which is why it is checked last: it is the least common cause here and the only one that is not an owner fix.
What to check first, second and third
- Check the set point and whether any demo or showroom mode is active — A control fault and a control setting look identical from the outside, and one of them is free to fix.
- Look at the freezer rear panel for a frost sheet — It separates a stopped air path from a stopped cooling system before any tool comes out.
- Feel the condenser area for heat and look at the coil — A coil that is hot and furred tells you where the heat is stuck.
The checks you can do yourself
- Read the set point, then switch the unit off at the wall for a few minutes and back on — A reset clears a latched control state. If cold returns and then fails again, the control is the suspect.
About 15 min
- Empty the freezer, switch the unit off at the wall and leave the doors open until all frost is gone — Cold returning afterwards names the defrost system as the cause and needs no part to prove it.
About 60 min
- Pull the unit out, vacuum the condenser coil and the fan grille behind or beneath it — This is the single most productive owner check on any refrigerator and it needs no skill.
Tools: a vacuum, a soft brushAbout 30 min
- STOP HERE: anything past this point needs gauges on the sealed system — That is licensed work and it is where an owner check ends.
Read this before you start
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Get help before pulling the cabinet out: a loaded unit runs away from you on a hard floor and the supply line behind it tears easily. Never open sealed-system tubing.
Where the owner fix ends
Call once the coil is clean, the gaskets pass the paper test and a full defrost has not restored cold. Call immediately for oil near the compressor or a burning smell: oil outside the tubing means the system is open. A refrigerator holds food safely at 40 degrees F (4 degrees C) or below, so treat a cabinet above that for hours as a food decision first.
Nearest pages of this class
What is deliberately not on this page
This page is written for the Thomson refrigerator as a class, not for one family or model line. Where a family-specific page exists for your unit it is linked below and it is the more specific answer. Deliberately not here: wiring colours, part numbers, board pinouts and service-mode sequences, which all differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
