Refrigerator Not Cooling, Fridge and Freezer Both Warm: What a Technician Tests

When the fresh-food side and the freezer are both warm, the refrigerator has stopped moving heat out of the cabinet, and the list of possible causes runs from a dusty condenser to a failed compressor. The parts that matter sit in three places: the machine compartment at the bottom back, the evaporator behind the freezer wall, and the control or inverter board. A technician reads them in a set order, cheapest and most common first, and does not condemn the compressor until the parts around it have tested good. Below is that order with the readings we expect. Read it as a technician’s checklist; several steps are done on live terminals.

This page covers the case where both compartments are warm. If the freezer is cold and only the fresh-food side is warm, the cause is usually airflow between them, and refrigerator not cooling but freezer is walks through that. If the refrigerator is completely dark and silent, start with refrigerator not turning on.

What a technician brings to this call

• A digital multimeter rated CAT III, with a capacitance range, plus a clamp meter for amp draw.
• Two probe thermometers, one for each compartment, and an infrared thermometer for coil and line temperatures.
• A condenser brush, a vacuum, and a coil cleaner for heavily loaded coils.
• For sealed-system work: gauges, a recovery machine, and the EPA Section 608 certification the law requires to handle refrigerant.
• The tech sheet, usually inside the machine compartment cover or behind the kick plate. It lists thermistor charts, compressor winding values, and the diagnostic mode.

Step 1: measure the compartments and listen to the machine

The display setting is not a reading. A technician puts probe thermometers in a glass of water on the middle shelf and in the freezer between packages and reads them after the doors have been closed for a while. The targets are 37 to 40°F in the fresh-food side and about 0°F in the freezer.

Then the technician listens and feels, with the doors shut, at the bottom back of the cabinet:

Demo mode is worth ruling out early. Samsung and LG models in showroom mode light up and run their fans with the compressor off. Samsung often shows OF OF on the display. The exit sequence is in the manual.

Step 2: the condenser and its fan

A refrigerator moves heat from inside the cabinet to the condenser coil, and the condenser fan pushes room air across that coil to carry the heat away. When the coil is matted with dust and pet hair, or the fan stops, the refrigerant cannot shed heat, head pressure climbs, and the compressor runs hot and long without cooling much. In South Florida this is aggravated by refrigerators in garages, where the air around the coil can sit well above 90°F for months. Many manufacturers rate their units for a room range that tops out around 90 to 110°F, and a garage in July can exceed it.

With the unit unplugged and the rear panel off, the technician brushes and vacuums the coil, spins the fan blade by hand (it should turn freely and coast), and checks the motor. Many condenser fans on current refrigerators are DC motors driven by the board, so a resistance check means little. The test is voltage at the fan connector with the compressor running, which is a live test in a tight space next to a spinning blade.

Clean coils and a running fan that cures nothing still give you information. The discharge line from the compressor should be hot to the touch and the condenser warm along its length. A condenser that is barely warm while the compressor runs means the system is not pumping heat, and that points to the sealed system.

Step 3: the start components on a conventional compressor

On a single-speed compressor (much of GE, Whirlpool and Frigidaire production, and older units of every brand), a start relay and an overload protector clip onto the compressor terminals. The relay gives the start winding a brief jolt, and the overload cuts power if the compressor draws too much current or gets too hot. Either one failing gives the classic click and hum every few minutes.

With the power off and the relay pulled from the terminals:

The exact winding values are on the tech sheet or the compressor label. Good windings do not prove a good compressor. A compressor can have perfect windings and a locked mechanism, or worn valves that let it run without pumping. The next check is amp draw with a clamp meter while it starts and runs, compared to the rating on the label. A locked rotor shows a high spike and then the overload trips. A compressor that runs at well below rated current with a cool condenser is not moving refrigerant.

Low voltage causes the same click. A refrigerator on a long extension cord, a shared garage circuit, or a building with sagging line voltage can fail to start a healthy compressor. The outlet should read close to 120 V, and it should hold near that while the compressor tries to start.

Step 4: inverter compressors on LG, Samsung and newer Whirlpool and GE units

An inverter refrigerator has no start relay. The board converts line power to DC and then drives the compressor at variable speed through three output wires. LG’s linear compressor is a different design again, driven by LG’s own inverter circuit. These compressors cannot be started by applying wall voltage to the terminals, and trying to do so damages them.

The technician reads them differently:

• Winding check with the power off and the capacitors discharged: on a three-terminal inverter compressor all three pairs should read about the same low resistance, close to each other within a small margin. One pair that reads open or very different points to the compressor or its harness.
• Board output: in diagnostic mode the board is commanded to run the compressor, and the technician checks whether the board produces output and whether the compressor responds. No output with good windings points to the inverter board. Output with no response points to the compressor.
• Codes: Samsung shows compressor and inverter faults in its 80-series codes, and 84C on many models means the compressor failed to start. LG shows fan and sensor errors such as Er FF and Er CF on the display, and deeper compressor faults in diagnostic mode.

LG and Samsung inverter compressors carry a ten-year part warranty on most models, so a confirmed compressor failure on those is often a labor-and-refrigerant job. Confirming it correctly is what makes the warranty claim stand up.

Step 5: the evaporator, the defrost system and the sensors

Behind the freezer’s back wall sits the evaporator coil and the fan that pulls air across it. Every few hours the control shuts off cooling and runs a defrost heater to melt frost off the coil. If the heater, the defrost thermostat or bimetal, or the defrost sensor fails, frost builds until it blocks the coil completely. The fresh-food side warms first, because it gets cold air only through ducts from the freezer, and the freezer follows. A wall of white frost behind the freezer panel confirms it.

With the power off:

• The defrost heater should show continuity. Its resistance follows from its rating, usually a few hundred watts at 120 V, which works out to tens of ohms. OL is a burned heater.
• The defrost thermostat on many Whirlpool, GE and Frigidaire units is closed only when cold, so it reads open at room temperature even when it is fine. It is tested cold, or replaced with the heater.
• Thermistors in most brands read from a few kilohms to tens of kilohms at room temperature, and the resistance rises as they get colder. The tech sheet has the temperature chart. A thermistor that reads open, near zero, or far off the chart gives the board a false temperature and it stops cooling or stops defrosting.

Melting the frost with the doors open brings the refrigerator back for a few days. The frost returns because the part that caused it is still there, and on some Samsung and LG French-door models the drain under the evaporator freezes as well, which is a heater and drain retrofit, not a defrost.

Step 6: the sealed system

When the coils are clean, the fans run, the compressor starts and draws reasonable current, and the cabinet still warms, the problem is inside the sealed system: a refrigerant leak, a restriction in the capillary tube or filter drier, or a compressor that runs without pumping. The signs a technician looks for are a condenser that stays cool, an evaporator with frost on only the first few inches of tubing, oil spots at joints, and a hissing or gurgling sound that is different from normal refrigerant flow.

Sealed-system work requires EPA Section 608 certification. It involves recovering the remaining refrigerant, finding and repairing the leak, replacing the drier, pulling a deep vacuum and weighing in the exact charge printed on the data plate. On R-600a units that charge is a few ounces, and an error of a fraction of an ounce changes performance. Whether it is worth doing depends on the age of the refrigerator, and on a ten-year-old unit the honest answer is often that it is not.

After a power outage or a storm

A refrigerator that runs but will not cool after an outage usually falls into one of three cases. Some simply need time: a warm cabinet full of warm food can take a day to pull down to temperature. Some lost a board to the surge when power came back, and the control now reports nothing or calls for nothing. And some had a weak start relay or compressor that the outage finished off. The tests above separate them. For what a surge does to refrigerator electronics and how to protect one, see power surge and refrigerator control boards, and for compressor warning signs before it fails, signs a refrigerator compressor is failing.

What our technician does on a no-cool call, and what it costs

Compartment temperatures, a listen and feel at the machine compartment, the condenser and fan, start components or inverter output, the compressor windings and amp draw, the evaporator and defrost circuit, and the sealed system last. Typical South Florida prices with parts and labor, from our current price pages:

• Condenser cleaning or condenser fan work: $130 to $280
• Start relay and overload: $130 to $240
• Evaporator fan or defrost control: $180 to $340
• Main control board: $250 to $480
• Inverter board: $260 to $460
• Sealed-system leak repair: $500 to $800
• Compressor with the part under the maker’s warranty: $420 to $680. Out of warranty: $900 to $1,700.

We repair every refrigerator brand across Miami-Dade, Broward and Palm Beach, seven days a week, built-in units included. The service call is $59 and it is credited to the repair when you go ahead. Call (754) 345-4515, or see refrigerator repair. Brand pages: LG, Samsung, Whirlpool, GE, Frigidaire. Garage units have their own problems, covered in garage refrigerator not cold in Florida heat, and LG owners with a linear compressor should read LG linear compressor failure.

Questions owners ask