The short answer
On a Simplex refrigerator, an ageing defrost system is the first thing to suspect, ahead of frost blocking the evaporator, with the evaporator fan motor at the bottom of the list. On a long-serving machine the ranking leans towards what wears — seals, mounts, hoses and switches — rather than towards anything with a circuit board in it. More than one of the checks below needs no tools at all, and the last of these causes is a service call.
What you observe
- Food in the door is spoiling first — The door is the warmest part of the cabinet, so it shows a small temperature rise soonest.
- The fridge is warm but the freezer is still cold — Classic split: cold is being made and is not being moved into the fresh-food side.
- Condensation or sweating inside the cabinet — Warm humid air is getting in, which points at a door or a seal rather than at the machinery.
- NEAR MISS — only the ice maker has stopped — Ice production has its own causes; the ice page for this appliance is the right read.
Causes, most likely first on Simplex
- An ageing defrost system — On an older frost-free unit the defrost heater, its thermostat and its timer have all been through many thousands of cycles. When one of them gives up, the coil ices over and the cabinet warms — slowly, over weeks. Placed there because age puts the defrost system first: it is the part of an old frost-free unit most likely to have worn out.
- Frost blocking the evaporator — Second here, and on most machines it would be at the top: a unit that recovers after being left off overnight has confirmed this cause and no other.
- Thermostat, thermistor and the control settings — The settings are free to check and they explain a surprising number of complaints, especially on units where the controls are inside the cabinet and can be knocked by a package. Third, once the two above are clean: checking a setting costs nothing, which is why it belongs above anything that requires a panel to come off.
- The evaporator fan motor — The distinguishing test is sound. Last: it ranks here because one listening test separates it from the cause it imitates.
Check in this order, and why
- First: Does it recover after a defrost, then relapse? — Recovery followed by a relapse within weeks is the defrost system rather than the cooling system. It is first because it is the cheapest of the three to settle.
- Second: Look at the freezer rear panel for frost — A sheet of ice rather than a light dusting tells you the air path is blocked.
- Third: Check the setting and put a thermometer inside — A refrigerator holds food safely at 40 °F (4 °C) or below. Measure rather than guess.
What an owner can safely check
- Empty the unit and leave it off with the doors open — Let it defrost fully, dry it, and restart it. Cold restored afterwards confirms the defrost system.
Tools: towelsAbout 60 min
- Verify the setting and measure the temperature — Put a thermometer in a glass of water in the middle of the fridge and read it after several hours.
Tools: fridge thermometerAbout 30 min
- STOP HERE if the next step needs a meter on live terminals — That is the line between an owner check and a service call, and it is not worth crossing.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel, and treat every capacitor as still charged: a capacitor can hold a charge after the power is off. Do not attempt anything on the sealed system: refrigerant work is licensed work. Never chip ice off an evaporator with anything metal, because piercing a coil ends the appliance.
When to call a technician
The owner side is the coil, the seals, the vents and a full manual defrost. Past that, the panels come off and the unit is worked on isolated.
Nearest pages of this class
What this page does not cover
This is generalized information for Simplex refrigerators as a class, not for one family or one model. No family- or model-specific page for this brand and appliance is published here yet, so nothing narrower is linked; when one is, it becomes the more specific answer and this page will point to it. No part numbers, no wiring detail, no dismantling sequence: those vary by family and are only useful beside the family they describe.
