The light inside the refrigerator should turn off when you close the door. If the light stays on, the regular incandescent light bulb can get very hot. This heat can cause a burning smell from the refrigerator. Check that the light is wired correctly and the door switch is working properly.
The compressor start relay, also called a start device or start relay and overload kit, may have malfunctioned, typically preventing the compressor from starting. If a burning odor originates from the compressor, inspect the start device. If the start device is burnt or the compressor attempts but fails to start, the start relay likely needs replacement. A burnt smell from the faulty start component indicates it should be replaced to allow proper compressor function.
The compressor start device, also called a start relay, helps start the refrigerator compressor. If this device fails, the compressor may not turn on at all. If you smell a burning odor coming from the compressor, the start device could be faulty. Check if the compressor is trying but failing to start up. Also inspect the start relay to see if it smells burnt. If so, the start device is probably bad and needs replacing. This is a common reason refrigerators have a burning smell and the compressor won't start.
If you smell a burning odor coming from the outside of the refrigerator, the condenser fan motor may be overheating. Inspect the fan motor for any burn marks, focusing on the wire connections. Use a multimeter to check for electrical continuity through the motor windings. This can verify if the motor has burned out. Condenser fan motors can wear out over time and overheat. Burn marks or failed continuity tests indicate the fan motor needs replacement.
The refrigerator light can stay on constantly if the door switch shorts closed. This leaves the incandescent bulb powered on even when the door is shut. The bulb can overheat and cause a burning smell. Use a multimeter to check the electrical continuity on the door switch. Test it before and after opening and closing the door. If the switch shows continuity in both positions, it is stuck closed and needs replacing.
Check the refrigerator power cord where it plugs into the wall outlet for any burn marks. Also inspect the wall receptacle. The power cord should fit snugly into the outlet. If the cord or outlet feels hot, that indicates a poor connection. Any burn marks or damage to the cord means it needs replacement. If the cord is loose in the receptacle, the outlet should be changed by a licensed electrician. A loose power connection can overheat, causing burning smells.
Closely examine the refrigerator wiring and connectors near where you smell the burning odor. Check for any wires that look damaged, pinched, or improperly connected. Also inspect for loose, corroded, or burnt connections at the wire terminals. These issues can cause wires to short circuit and overheat, producing a burning smell.
Faulty refrigerator components can fail in a way that causes a burning odor. Inspect the area where you smell burning for stuck or seized up fan motors. Also check for any control boards that look overheated or burnt. These parts can short circuit internally and smell hot. Determine if the burning smell directly traces to a failed component. Replacing burnt out fan motors or control boards will stop the overheating and burning odor.
The main control board is the brains of the refrigerator, controlling all of the components that regulate temperatures and enable cooling. If the control board is defective, it can malfunction in ways that lead to overheating of parts. This overheating can produce a burning or electrical smell. The control board may fail to properly turn the compressor and condenser fan off at the right times, leading to overheating of the compressor motor windings. Or it may continuously run the defrost heater, causing the defrost termination thermostat to overheat. The control board itself contains capacitors and relays that can overheat and burn out from voltage spikes or general failure. As the control board components burn out, they emit a distinctive burning odor.
The evaporator fan circulating cold air can seize up and stop spinning. This can make the fan motor overheat and smell burnt. Check that the evaporator fan blade rotates freely by hand. If the blade is stuck or frozen, the motor windings will burn out from straining to turn it. Replace the evaporator fan motor if the blade does not move freely.
The refrigerator light bulb can overheat and cause a burning smell if the light stays on constantly. An incandescent bulb gets hot when illuminated long-term. Use a multimeter to check the electrical continuity of the light switch. Test it before and after flipping the switch. If the switch shows continuity in both positions, it is stuck closed and needs replacing. This will make the light stay on even with the door closed. Replacing a shorted light switch will stop the constant power to the bulb. The new switch will turn the light off when the door closes.