Refrigerator Not Cooling With Frost on the Freezer Wall: Defrost Repair Cases

A Whirlpool side-by-side stopped cooling and the rear freezer wall was solid with frost. Another company had already diagnosed it as a failed defrost heater. The heater tested fine. The real fault was the evaporator thermistor, and the repair came to $340.

Job details

Model: Whirlpool WRS315SNHM06
Symptom: Refrigerator not cooling, heavy frost on rear freezer wall
Suspected: Defrost heating element
Actual cause: Evaporator thermistor out of range
Fix: Manual defrost of the evaporator coil, thermistor replaced
Cost: $340
Location: Galaxy Way, Century City, CA 90067

What the client reported

Food in the fresh food section was going warm and the freezer was working harder than usual. When she opened the freezer and pulled things out, the whole back panel was covered in snow-like frost. A company had already been out, run a diagnostic, and quoted a defrost heater. She asked me to arrive with that part in hand.

Why frost alone does not identify the failed part

Heavy frost can restrict airflow and leave the refrigerator compartment warm. The heater is one part of the automatic defrost system; depending on the model, the circuit also involves a bimetal thermostat, temperature sensors, wiring and electronic controls. Testing is needed to identify the failed component.

In this Whirlpool repair, the heater was working and the evaporator thermistor was out of range. The Kenmore repair below had a different failed component: the bimetal defrost thermostat. Similar symptoms do not always require the same part.

What it actually was

Before installing anything, I tested the heater in place. It had continuity and drew normal current, so it was not the failed component. I then checked the evaporator thermistor resistance against coil temperature. It was reading well out of range, which explains why no defrost cycle had run.

The repair

The evaporator coil was fully iced, so it had to come off slowly rather than with heat guns or scraping, which is how coils and aluminum tubing get damaged. Once the coil was clear, I removed the rear freezer panel, replaced the thermistor, and reassembled everything. About an hour on site. Temperatures pulled down normally the same visit.

What it cost

$340 total, parts and labor. Replacing the heater instead would have cost the client money and left the fridge frosting up again within a few weeks.

Kenmore Defrost Repair in Pico-Robertson, Los Angeles 90035

Completed October 19, 2026, by Oleg at Vertex Appliance Repair. A Kenmore 596.69313010 refrigerator had little or no cold airflow into the fresh food compartment. The repair was completed by replacing the defrost thermostat together with its wiring harness. The total for this job was $352: $112 for the part and $240 for labor.

What we found

The air damper opened and closed, and the evaporator fan was running, but cold air was not coming through the damper. Inspection of the freezer evaporator found heavy frost buildup restricting airflow. The failed component identified during diagnosis was the bimetal defrost thermostat.

Why a working damper did not mean normal airflow

An open damper provides a passage for air; it cannot overcome an evaporator blocked by frost. This is why checking the damper alone would have missed the cause in this refrigerator. Frost buildup points to a problem that needs diagnosis, rather than proving that the damper, heater or control board must be replaced.

Completed repair and actual cost

For this job, we replaced the defrost thermostat as part of the wiring harness assembly. A bimetal defrost thermostat switches the heater circuit according to temperature; it is different from the resistance-based thermistor replaced in the Whirlpool case above.

• Appliance: Kenmore refrigerator, model 596.69313010
• Service area: Pico-Robertson, Los Angeles, CA 90035
• Part: defrost thermostat and wiring harness assembly — $112
• Labor: $240
• Completed repair total: $352
• Warranty: 90 days on the completed repair and installed part

This is the actual price of this repair on October 19, 2026, not a fixed quote for every refrigerator with similar symptoms. The required part and repair cost depend on the model and diagnosis.

For a similar cooling or frost problem, see our in-home refrigerator repair service. Vertex is based in West Hollywood and serves nearby neighborhoods, including Pico-Robertson. Call or text 323-747-7098; share your ZIP code and model so we can check coverage and availability. The diagnostic visit is $89, credited toward approved repair.

Frequently asked questions

Why is there snow on the back wall of my freezer?

Heavy frost can indicate a defrost problem and can block airflow through the evaporator. Door sealing and air leakage also need to be checked; frost alone does not identify a failed part.

How do I know if it is the heater or the sensor?

A technician checks the heater and the model-specific defrost circuit. That may include testing a bimetal thermostat while cold, checking a thermistor against its temperature-resistance specification, and inspecting wiring and controls. A thermostat and a thermistor are different components.

Can I just unplug the fridge to melt the ice?

Melting the ice can temporarily restore airflow, but it does not repair a failed defrost component. If the underlying fault remains, frost can return. Protect perishable food and arrange diagnosis.

Refrigerator problem in West Hollywood?

See refrigerator not cooling repair in West Hollywood or call 323-747-7098.