The short answer
When the BBBF family stops cooling while the compressor still runs, the fault is usually that cold air is not moving rather than that cold is not being made. This page ranks the causes for that build; the brand-generic article ranks them for the brand as a whole.
What you observe
- A sheet of frost on the evaporator or the rear wall — A stalled defrost: the ice itself is now blocking the air path.
- Freezer side still cold, fresh-food side warm — Near-diagnostic on a shared-evaporator cabinet, and it points at the air path rather than the system.
- Cooling recovers for a day after the doors are left open — Near-diagnostic for a defrost fault: melting the ice restores the air path temporarily.
- The compartment is colder at the bottom than the top — An air-distribution problem rather than a failure to make cold.
- NEAR MISS - silent and not cold — That is a no-power or start-relay fault and belongs on a different page.
Causes, most likely first on BBBF
- Evaporator or circulation fan not running — Ranked first on the BBBF family: the fan is the one part in the cold side that turns continuously, and a cabinet that warms from the top down is usually telling you it has stopped. Every model code in the table above shares the same air path, which is why this ranks above the sealed system rather than below it. This moves above blocked airflow from a frosted evaporator, which leads the brand-generic order, because this family is a single build with fixed access points.
- Blocked airflow from a frosted evaporator — Second: ice on the evaporator is not a side effect but the blockage itself: once the fins are bridged, the cabinet is sealed off from the only cold surface it has.
- Door seals, door alignment and loading — Third: a heavy built-in door can drop on its hinges and leave a gap at one corner that is invisible until tested.
- Condenser coil choked or its fan stalled — Fourth: heat has to leave the cabinet somewhere, and a coil matted with dust or a stalled compartment fan means the machine runs without ever winning.
- Sealed-system or compressor fault — Last: last, and on a built-in it usually means the cabinet comes out of its housing.
Check in this order, and why
- Listen at the cabinet for the circulation fan — It separates the two likeliest causes before any panel comes off.
- Compare the two compartments against each other — One cold and one warm is an air path; both warm is the system or the condenser.
- Look behind the rear panel for a frost sheet — A solid sheet rather than a light dusting confirms a defrost fault.
- Test each door seal with a sheet of paper — Last, because it explains a struggling cabinet rather than a warm one.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Refrigerant work is licensed work, so leave the whole sealed system to a licensed technician, and call at once if you see oil at the compressor or smell burning.
When to call a technician
A refrigerator holds food safely at 40 °F (4 °C) or below and a freezer at 0 °F (−18 °C) or below; move perishables once the cabinet is above that. Cleaning a condenser and testing seals are owner work. Call as soon as the sealed system is suspected, because refrigerant work is licensed work.
Other BBBF pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
