my black and decker 2.5 fridge is running but not getting cold at all, freezer is just cool. what gives?

Diagnosis

The most common cause for a BLACK+DECKER BCRK25V refrigerator running (compressor humming) but failing to cool the main cabin is a failure in the refrigerant cycle or a blockage in the airflow. In this specific 2.5 cu ft model, the freezer section acts as the primary evaporator. If the freezer is "just cool" but not freezing, you likely have a slow refrigerant leak or a failing compressor valve. Because the main compartment relies on cold air dropping from the freezer, any inefficiency in the freezer section is magnified in the fridge below. Another frequent culprit is a "frozen-over" evaporator coil. If the door seal is leaking or the unit was overloaded, ice builds up on the internal coils, insulating the refrigerant from the air. This prevents the heat exchange process. You can confirm this by checking the back wall of the freezer; if you see a thick sheet of ice rather than light frost, the airflow to the lower cabin is completely blocked. If the compressor is running constantly without cycling off, the unit is struggling to reach the thermostat set-point due to these cooling failures.

How to Fix It

To resolve cooling issues caused by ice blockage or sensor errors, perform a hard thermal reset and airflow optimization:

1. Complete Defrost: Unplug the unit from the wall outlet. Empty all food from both the freezer and the main cabin. Leave the doors open for at least 24 hours. Do not use a hairdryer or knife to scrape ice, as you can easily puncture the aluminum evaporator lines.
2. Clean the Condenser Coils: Locate the back of the unit. Use a vacuum with a brush attachment to remove all dust, pet hair, and debris from the black condenser coils and the compressor area. If the coils are clogged, the heat cannot escape, and the fridge will stay warm.
3. Check Door Gaskets: Inspect the rubber seals around the doors. Take a piece of paper, place it halfway in the door, and close it. If the paper slides out easily, the seal is failing. Clean the seals with warm soapy water to remove sticky residue that might be preventing a tight seal.
4. Thermostat Calibration: Plug the unit back in. Set the temperature dial to the "Medium" or "4" setting. Avoid setting it to the maximum immediately, as this can cause the evaporator to freeze over again too quickly.
5. Airflow Clearance: Ensure there is at least 2 inches of clearance between the back of the fridge and the wall, and 1 inch on the sides. This model requires significant ventilation to dissipate heat.

If That Didn't Work

• Check the Start Relay: If you hear a periodic "clicking" sound coming from the back of the unit every few minutes, the compressor start relay has failed. This is a small plastic component plugged into the side of the compressor. Replacing this part (typically a generic 1/10 HP start relay) can restore cooling if the compressor was struggling to kick over.
• Inspect the Thermostat Sensor: The temperature probe may have shifted or become coated in ice. Ensure the sensor is not touching the back wall of the unit, which can trick the thermostat into thinking the unit is colder than it actually is, causing the compressor to shut off prematurely.
• Refrigerant Leak Assessment: If the compressor is hot to the touch and running 24/7, but the freezer is only 40-50°F, you likely have a puncture in the coolant lines. Because these units use a sealed system, a leak cannot be patched with a spray; it requires a professional vacuum and recharge, which often exceeds the cost of a new 2.5 cu ft unit.
• Power Cycle the Logic Board: Some versions of this compact model have a basic electronic controller. Unplug the unit for 30 minutes to clear any "glitched" states in the control board before restarting.

Heads Up

• Avoid Overstuffing: Do not pack food directly against the back wall of the freezer. This blocks the vents and leads to the "cool but not cold" symptom you are experiencing.
• Leveling is Key: Ensure the unit is perfectly level using the adjustable feet. If the unit tilts forward, the door may not seal properly, allowing warm air to seep in and cause frost buildup.
• Avoid Extension Cords: Never plug a compact fridge into a power strip or thin extension cord. These units require a stable voltage to start the compressor; low voltage can cause the compressor to overheat and fail.