Sub-Zero Refrigerator Repair in Toronto — Freezer cold but fridge warm

• Freezer-cold / fridge-warm is the textbook Sub-Zero dual-refrigeration fault: each compartment runs its own dedicated compressor and evaporator, so the freezer holding while the fresh-food side drifts warm means the refrigerator-side system alone has failed, not a shared damper or 'the compressor.' The most common single-side cause is a stalled refrigerator-section evaporator/circulation fan: the OEM service motor is 7003817 (it replaces the original Panasonic-style motor and, per Sub-Zero fitment, serves the refrigerator-section position on 700BC/I-3 and both positions on 700TC/I-3, 736TC/I-3 and 600-series units). When that fan stops, the fridge coil makes cold the cabinet never receives. We spin-test the blade and check winding continuity, and we position-verify by model/serial before ordering since the same number serves either side.
• Sub-Zero gates the fan diagnosis behind its own door-switch airflow check before we condemn the motor: with the fridge door open we hold the door switch closed and listen for gentle air from the rear vent panel - silence on the fresh-food side with a cold freezer is the fan-fault signature. We also confirm food and bins are kept clear of the rear diffuser/vents per Sub-Zero's guidance to leave at least a half-inch clearance at the interior air vents, because items packed against the diffuser starve the fresh-food compartment and read as a 'warm fridge' with zero broken parts - the cheapest fix on this call, and one we rule out before quoting the 7003817.
• A fridge that runs warm because its own evaporator has iced over throws EC24, Sub-Zero's defrost-underheat flag - the control saw a defrost cycle run longer than it should, meaning a high probability the coil is frosted and choking airflow into the fresh-food cabinet while the independent freezer side stays cold. We run Sub-Zero's manual-defrost test (hold the ice-maker key to the click, energize the heaters ~15-20 min) and watch whether the coil clears; a coil that won't melt points at the defrost heater or terminator, not the fan. On 532/632-class cabinets the OEM defrost heater is 7016048 (it supersedes to 4324690 on 632 units at/above serial #1810000 - a serial break we confirm at the OEM parts list before ordering), and the defrost terminator on IC/IT/ID columns is 7025952; we meter heater continuity in defrost mode before fitting either.
• When the fresh-food side runs warm with no fan or frost fault, the refrigerator thermistor circuit is the next stop, and Sub-Zero splits it into two codes that are both refrigerator-side: EC05 ('refrigerator repeatedly read erratic temperatures' - the cabinet sensor) and EC06 ('refrigerator evaporator thermistor read open or shorted for 10+ seconds or repeatedly read erratic temperatures'). When the board can't trust the fridge temperature it mismanages cooling and defrost timing on that system alone, so the compartment drifts warm while the freezer holds. The OEM refrigerator temperature-sensor assembly is 4204150 (fits 400/600/700 series prior to serial #2970000, with serial-coded variants on 427/427R and 700x/I-3 builds); we ohm the probe in ice water against the manufacturer's NTC resistance chart - a healthy refrigerator thermistor reads about 32,330 ohms at 32 F - and replace the sensor rather than chasing the sealed system.
• A surprising share of 'fridge warm, freezer fine' calls are not a failure at all: the refrigerator zone has been turned off or disabled at the control. Sub-Zero's official warm-refrigerator guidance says to confirm the section wasn't disabled - a zone that's off shows double dashes (--) on the panel while the freezer keeps running normally - and the documented fix is to reset the unit at the home breaker for 30 seconds, then allow up to 24 hours to recover. We always confirm the zone is enabled and reset before quoting any refrigerator-side part, because a new fan or thermistor won't 'fix' a compartment the control was told to switch off.
• On legacy 500-series-era cabinets (532, 550, 561) a fridge that warms gradually over weeks while the freezer holds points at refrigerator-side evaporator corrosion and a slow refrigerant leak - the 561 fresh-food evaporator is a well-documented field leaker (Sub-Zero later changed the coil material on these systems), eroded by food acidity. The fridge compressor runs but capacity bleeds away; gauges read low or negative on that side only. Because the refrigerator is its own sealed circuit, this presents as single-side warming rather than total loss, and it is true sealed-system work (recover, repair the coil/leak, evacuate, recharge) - legally certification-gated in Ontario, requiring a valid ODP refrigerant-handling card under O. Reg. 463/10, never a parts-swap.
• Sub-Zero gives a hard go/no-go threshold for this symptom that we honour before quoting: if the fresh-food compartment is near setpoint and the condenser hasn't been cleaned in 6 months, we brush-and-vacuum the shared lower-grille condenser and let it recover; but if the fridge reads about 48 F with the dial set to 38 F, Sub-Zero says it's unlikely to recover from a condenser cleaning and to escalate to Factory Certified Service. That 10-degree gap is our trigger to stop cleaning and move to the fan, thermistor (EC05/EC06), defrost (EC24), or sealed-system diagnosis rather than billing a maintenance visit that won't hold.

Sub-Zero freezer cold but fridge warm in Toronto — the local specifics

• The recurring Toronto pattern on 'freezer fine, fridge warm' Sub-Zero calls is that the fault is single-side by design and resolves at the refrigerator-side air path far more often than at the sealed system: a stalled fresh-food evaporator fan (7003817), an iced fridge coil throwing EC24, packed internal vents below Sub-Zero's half-inch clearance, or - on a meaningful share - a refrigerator zone that was simply switched off at the panel and just needs a breaker reset. We see the condenser-cleaning-won't-recover threshold (about 48 F when set to 38 F) often enough that we check it first to decide whether to clean or escalate, and we keep legacy-561/532 evaporator corrosion on the differential as a separate sealed-system path.
• We bring the 7003817 refrigerator-side evaporator fan motor and the 4204150 refrigerator temperature sensor (EC05/EC06) as the two parts that close most of these calls in one visit, plus a 4204490 water filter and 7042798 air cartridge to refresh while the cabinet is open. We confirm model/serial before the visit so serial-coded defrost parts (7016048/4324690 heater, 7025952 terminator) come on the right truck, and we carry meter and manual-defrost tooling to verify the fan, thermistor, and defrost circuit on site rather than blind-swapping a several-hundred-dollar fan.

For the full Sub-Zero refrigerator module — every fault, part number and code — see Sub-Zero refrigerator repair in Toronto, and for the same fault across all brands the refrigerator freezer cold but fridge warm guide.