If your freezer is packed with thick ice, your fridge isn’t staying cold, or airflow feels blocked behind the back panel, your refrigerator is likely not defrosting properly. It’s a warning sign that your appliance is working harder than it should, risking compressor damage, food spoilage, and higher energy bills.

At Just Call Appliance Repair, we see defrost failures weekly across all major brands. While some issues look like simple frost buildup, the real problem is often hidden in the defrost heater, thermostat, or control system. Understanding what’s broken, and what’s safe to handle yourself, is the first step toward a lasting fix.

How a Refrigerator Defrost System Is Supposed to Work

Modern fridges run automatic defrost cycles every 8 to 12 hours. During this cycle, a heater briefly activates to melt frost off the evaporator coils. The water then drains through a small tube into a pan near the compressor, where it evaporates. When this system fails, ice accumulates, airflow drops, and cooling suffers, starting in the freezer, then spreading to the fresh food section.

Why Your Refrigerator Is Not Defrosting

Here are the most common causes we diagnose as an appliance repair company:

1. Defrost Heater Failure

Behind the freezer panel is a thin wire element that serves as the heater. It may eventually burn out as a result of age or exposure to moisture. Ice accumulates quickly, so if it malfunctions, there is no melting. For Frigidaire, Whirlpool, and GE models older than five, this is the leading cause.

2. Faulty Defrost Thermostat

The heater is informed when to shut off by this tiny sensor, which is located close to the evaporator coils. It completely cuts off power to the heater if it malfunctions while in the open position. Upon inspection, you will frequently discover that it is cracked or brittle.

3. Control Board or Timer Malfunction

Electronic control boards have replaced mechanical timers in more recent refrigerators. The entire cycle skips if the board fails to send the defrost signal because of component wear, moisture, or a power surge.

4. Clogged Defrost Drain

Even if defrost runs, a blocked drain tube traps melted water. It refreezes, creating ice dams that restrict airflow and mimic heater failure. This is especially common when food particles or mold clog the drain hole inside the freezer compartment.

DIY Checks You Can Try

Before calling a technician, you can perform a few low-risk checks, but only if you’re comfortable working with appliances and always unplug the unit first:

• Manually defrost the unit: Unplug the fridge, remove food, and leave the doors open for 24 hours. If cooling returns afterward, the defrost system likely failed.
• Inspect the evaporator coils: Remove the freezer back panel (if accessible). Heavy frost covering the coils confirms a defrost issue.
• Check the drain hole: Located at the bottom of the freezer compartment. Clear minor clogs with warm water and a turkey baster.
• Listen during a defrost cycle: If your model has a mechanical timer, you may hear a click followed by a faint hum (the heater activating).

Important: Do not attempt to test the heater or thermostat with a multimeter unless you’re trained. These components run on line voltage, and incorrect handling can cause shock or fire. Also, never chip away ice with sharp tools, you can puncture refrigerant lines.

When to Call a Professional Appliance Repair Company for a Fridge Defrost

Contact us if:

• Manual defrost restores cooling temporarily but ice returns within days
• You see error codes on a digital display (e.g., “DF,” “FF,” or “E5”)
• The freezer is silent during what should be a defrost cycle
• You smell burning or notice melted plastic near the back panel
• Your fridge is a Samsung, LG, or high-end GE with sealed electronics

As a professional appliance repair company, we use precision tools to test continuity, voltage, and control signals, so we replace only what’s truly broken, not guess based on symptoms.

How To Diagnose and Fix Defrost Failures

Our technicians follow a systematic process:

1. Verify frost pattern and airflow blockage
2. Test defrost heater resistance (should be 20–50 ohms)
3. Check thermostat continuity when cold (should read closed)
4. Inspect the control board signals during forced defrost mode
5. Clear and flush the drain system to prevent recurrence

We carry common defrost components for repairs on GE, Whirlpool, Samsung, LG, Frigidaire, and KitchenAid models and we always test the full cycle before leaving.

How To Prevent Fridge Defrost Problems

Once repaired, these habits help your defrost system last longer:

• Clean the condenser coils every six months
• Ensure the fridge isn’t overpacked, air needs to circulate
• Wipe spills quickly to prevent drain clogs
• Avoid frequent door openings during high-humidity days
• Replace worn door gaskets promptly to reduce moisture intake

A refrigerator that can’t defrost properly won’t cool efficiently, no matter how cold you set the dial. If you’re seeing ice buildup, warming temps, or blocked vents, don’t wait for total failure. We’re ready to diagnose and repair your fridge system correctly, with transparency and expertise you can trust.