The short answer
Start from a control board or thermistor giving the wrong picture: on a Sunstone refrigerator that is the likeliest explanation for what you are looking at, and a sealed-system or compressor fault is the least likely. Most of this you can settle before anyone is called.
What the symptom looks like
- Frost has built into a sheet on the freezer back wall — Not the usual light dusting but a solid layer, which is airflow stopping rather than cold failing.
- The compressor never cycles off — It runs continuously without ever reaching temperature, which is the same fault seen from the other end.
- 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. First here, for a reason specific to Sunstone: an outdoor cabinet attacks the gaskets and the supply lines long before it touches anything mechanical.
- 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 here: outdoor air carries dust and pollen straight into the intake, and the restriction builds faster than anyone expects.
- Door gaskets no longer sealing — A hardened gasket lets room air in continuously. The unit runs without stopping and the interior never settles. Third, once the two above are clean: sunlight and a daily temperature swing harden a gasket far faster outdoors than the same gasket hardens inside.
- 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, and the order is the point: it is the least common cause here and the only one that is not an owner fix.
Check in this order, and why
- 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.
- Close the door on a sheet of paper and pull it out — Anywhere it slides out freely is a gap the unit is fighting all day.
Owner checks, in order
- 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
- Test the gasket with a sheet of paper at several points around each door — Wash the gasket and the frame first. Food residue holds a gasket open more often than age does.
Tools: a sheet of paperAbout 15 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.
Safety first, and it is not a formality
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.
Closest pages to this one
What is deliberately not on this page
This page is written for the Sunstone 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.
