KSSS42QKW00 Refrigerator Not Cooling – What Part Fixes This Problem?
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Understanding the Problem
When a KSSS42QKW00 refrigerator (or similar side-by-side/built-in unit) stops cooling properly, the underlying problem is usually one of a few systems: airflow (fans/evaporator frost), sealed refrigeration system (compressor, capillary/thermal expansion, refrigerant leak), or control/temperature sensors. Diagnosis starts with observing temperatures in the fresh food and freezer compartments, listening for the compressor and fans, and checking for excessive frost on the evaporator coil. Because this model line uses the same core systems found in most modern refrigerators, the stepwise troubleshooting approach works: verify power and controls, inspect condenser coils and condenser fan, check evaporator fan and for frost buildup, test thermistors/temperature sensors and the control board, and only then move to sealed-system checks (compressor operation, start device, and refrigerant). Sealed-system repairs (compressor or refrigerant) require certified HVAC/R service and specialized tools.
Common Symptoms
Freezer and fridge compartments warm; compressor runs constantly or cycles on/off rapidly; frost or ice buildup on evaporator; evaporator/condenser fan(s) not running; visible frost pattern on back wall of freezer; error codes or flashing lights on display.
Common Causes
- Blocked airflow or failed evaporator fan causing poor cold-air circulation
- Failed defrost system (defrost heater, defrost thermostat/bi-metal, or defrost control) leading to iced-over evaporator
- Sealed-system or compressor failure (loss of refrigerant, failed compressor, or bad start components) or failed control board/thermistor providing incorrect commands
Popular Parts That Fix This Problem
These are the most common replacement parts that fix this problem. When you're ready to order, click below to find the right part at ProsourceParts.com — just search by your appliance model number for a guaranteed fit.
Helpful Repair Tip
Quick confirm: with the unit plugged in and at normal settings, open the freezer and listen for the evaporator fan. If the freezer is warm and you hear the compressor running but no evaporator fan, start with the evaporator fan motor and its harness; if the fan runs but there's frost covering the evaporator, suspect a defrost system failure (defrost heater, thermostat, or control).
Frequently Asked Questions
Can I replace parts myself to fix a KSSS42QKW00 that isn't cooling?
You can replace user-accessible parts yourself, such as evaporator or condenser fans, thermistors, door gaskets, defrost heater (if accessible), or start relays — provided you have basic tools and follow safety steps (unplug unit, discharge capacitors where applicable). Avoid sealed-system work (compressor or refrigerant) unless you are a certified technician with proper tools and EPA certification.
How do I tell if the problem is the compressor/sealed system versus a fan, defrost or control issue?
Start by listening and observing: if the compressor runs (you can feel vibration and hear steady hum) but the freezer is warm and the evaporator fan is running, and you see no frost on the evaporator, suspect a sealed-system issue. If the evaporator is iced over or the evaporator fan is not running, the problem is more likely defrost-related or an evaporator fan failure. Use a multimeter to check thermistor resistance and continuity of defrost components, and visually inspect condenser coils for heavy dirt. When in doubt, capture symptoms (temperatures, sounds, frost pattern) and consult a service technician for sealed-system diagnosis.
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