Here's what was behind the panel, what it took to fix it and what it cost, with the photos from both visits.
The call: freezer cold, fresh food warm
The booking note was shorthand: KitchenAid built-in, freezer cold, fresh food not cooling. The unit is a KBSN708, KitchenAid's 48-inch built-in side-by-side, the stainless two-door built-in that sits flush in a cabinet run. It is built by Whirlpool, and on this platform, like most side-by-sides, there is one evaporator and it lives in the freezer. A fan pulls air across the coil and pushes part of it through a duct and a damper into the fresh-food side.
That design is why the symptom is so specific. When the coil ices over, the freezer still feels cold, because a block of ice is cold. But air can no longer move through the fins, so the fresh-food side, which gets its cold second-hand, is the first to drift warm. Our technician arrived just after noon on Sunday, October 25, and had the freezer emptied within half an hour.
What a frozen evaporator means
Melting frost off the coil is the defrost system's job. Every so often, on a schedule the control sets from how long the compressor has run, it stops cooling and powers a heater that sits against the coil; on this model the data plate lists the defrost circuit at 450 watts. A thermistor on the coil tells the control when the ice is gone and cooling can resume. When the heater fails, frost builds a little thicker every cycle, for weeks, until the airflow to the fresh-food side is gone.
The frost pattern is the tell. A refrigerator that is low on refrigerant frosts only the first rows of its coil and leaves the rest bare. A coil that is white everywhere has been making cold just fine; either its frost was never melted off or air stopped moving across it. On this job the estimate written on the first visit listed the three things the repair would need: a manual defrost, a new heater assembly and a new thermistor.
First visit: price it, order the parts
A frozen coil can't be worked around, so the manual defrost went on the estimate alongside the two parts. A written estimate for the full repair, $722.42, was prepared on the spot and approved the same day, before any part was ordered.
The heater assembly and thermistor were ordered that afternoon from an appliance parts distributor and shipped by UPS. The first visit took just under an hour on site, estimate included.
Second visit: thaw it, swap the parts, close it up
The parts arrived and the second visit was Thursday, October 29. With the panel off, the coil was frosted solid from top to bottom, so the first job was the manual defrost: a block of ice has to come off the evaporator before anything else can happen, and it has to come off without touching the tubing. Then the old heater assembly came out, the new one went in against the coil, the new thermistor went on and was plugged into the harness, and the panel, drawers and shelves went back. The freezer was reloaded and the unit was left running. That visit took about an hour and forty minutes.
What it cost
Defrost heater assembly, $193.62. Thermistor, $35.33. Manual defrost, $150. Installation labor, $320. Sales tax on the parts, $23.47. Total, $722.42, the figure on the written estimate from day one. The $85 diagnostic was credited to the repair rather than charged on top. The heater and thermistor carry our 1-year parts warranty.
Why more than the same repair on a freestanding refrigerator? Two reasons. A 48-inch built-in has to be emptied and opened to reach the evaporator behind a full-height panel, and when parts have to be ordered that work is spread over two visits. And the thaw is its own job: a solid block of ice has to come off the coil before the new heater can go in, without damaging the tubing.
Our prices are written down before any work starts. The ranges we see most often are on our pricing page.
How to tell if your KitchenAid has the same problem
The fresh-food side creeps warm over days while the freezer stays frozen. There may be frost on the back wall of the freezer, or the air from the vents in the fresh-food side feels weak or stops. If you have unplugged the refrigerator for a day, found it working again for a few weeks, and then watched it fail the same way, that's the clearest sign of all: the thaw fixed the symptom and the dead heater brought the frost back.
What not to do is chip at the ice. The evaporator tubing is thin aluminum, and a screwdriver or a knife through it turns a defrost-heater repair into a sealed-system repair. If you need the refrigerator working tonight, unplug it, open the doors, put towels down and let it thaw on its own; then book the repair, because the frost will return.
We repair KitchenAid refrigerators across Los Angeles County and Ventura County, same-day when the schedule allows, seven days a week. In this neighborhood, start with KitchenAid repair in Los Feliz or refrigerator repair in Los Feliz, or call (747) 207-2030. A&Y Appliances is licensed by the California Bureau of Household Goods and Services, BEAR Lic. #49435.
Read next: a different cause of the same symptom, on a Sub-Zero, in Warm Fridge, Cold Freezer: Inside a Sub-Zero Evaporator Replacement.