Refrigerator Not Defrosting? Defrost Heater Assembly W11575359 – Fix Frost Buildup Fast
Frost accumulating on your evaporator coils is almost always caused by a failed defrost heater assembly. In most Whirlpool-built refrigerators, the defrost heater runs on a timed cycle to melt frost off the coils — when it fails, frost builds up unchecked, airflow is blocked, and the refrigerator loses its ability to cool. ⚡ Common failure point in Whirlpool, Maytag, KitchenAid, and Amana refrigerators. Part W11575359 is the genuine OEM replacement that restores the automatic defrost cycle and returns your refrigerator to full cooling performance.
❓ Is This the Right Part?
This is the correct fix if ALL of the following are true:
- ✔ Refrigerator powers on and compressor runs normally
- ✔ Freezer fan and condenser fan operate correctly
- ✔ Defrost timer and defrost thermostat have been tested and confirmed OK
- ✔ No error codes pointing to a control board or sensor fault
- ✔ ONLY problem is frost buildup on evaporator coils and loss of cooling
Not sure? Send us your model number — we'll confirm before you order.
🔧 Common Symptoms
- ❄️ Heavy frost or ice buildup on the back wall of the freezer — most common, what customers Google
- 🌡️ Refrigerator not cooling or struggling to maintain set temperature
- 🔇 Defrost cycle not running automatically
- 💧 Water pooling under crisper drawers or on the floor
- 🔊 Unusual sounds from the freezer compartment (fan hitting ice)
- ⚠️ Warm fridge, frozen freezer — classic blocked-airflow pattern
✔ If these symptoms match, this is the most likely failed component in the system.
✔ In most cases, replacing this defrost heater assembly restores normal operation immediately.
📦 Part Details
- Part Number: W11575359
- Type: Defrost Heater Assembly — genuine OEM, direct-fit replacement
- Replaces: OEM direct-fit defrost heater assembly — no modification required
- Brands: Whirlpool, Maytag, KitchenAid, Amana
With the evaporator panel already removed, replace the defrost thermostat (thermal limiter) at the same time — these two components work together and often fail in sequence. Doing both now saves a second disassembly and ensures the full defrost system is restored.
⚙️ Installation
Skill Level: Moderate — 45–75 minutes. Disconnect power before beginning. Remove freezer contents, shelving, and the evaporator cover panel to access the heater assembly. If heavy ice buildup is present, allow the freezer to fully defrost manually before replacing the part. After installation, test continuity with a multimeter before reassembling the panel.
💡 Pro Tip
The defrost thermostat (thermal limiter) and defrost heater are a system — one rarely fails without stressing the other. Replacing both during the same repair eliminates the most common cause of repeat defrost failures and keeps your refrigerator running reliably for years. It's a $15–$25 part that saves a $150+ service call.
Model Hub Pages: WRF535SWHZ, WRF535SWHV, WRF535SWHW, WRS325SDHZ, WRS321SDHZ, WRS588FIHZ, WRS571CIHZ, WRX735SDHZ, WRF767SDHZ, WRF954CIHZ, MFI2570FEZ, MFT2772HEZ, KRFC300ESS, KRFF507ESS
✓ Model-Specific Repair Pages
✅Compatibility & Cross Reference
Not sure about your model number? Call 1-877-899-7278 and we’ll help you confirm. All brand names are the property of their respective owners and are used for compatibility reference only.
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