The short answer
If a second fridge has an ice maker, the supply line is the first suspect and the room is the second: a long run through an unheated space freezes, and a valve behind a pushed-back cabinet is easily closed. Check freezer temperature too - ice needs real cold to release.
What you actually see and hear
- The mould is completely dry — No water arriving. Valve, line or a frozen section of supply.
- Ice production stopped during a cold snap — A supply line freezing where it passes through the unheated part of its run.
- Small or hollow cubes — Restricted flow, usually a partly closed valve or an old filter.
- Plenty of ice but it is fused into a block — The bin is not being used often enough, which is normal in a second fridge.
- NEAR MISS - no ice maker at all in the freezer section — Many second fridges never had one. Look for a water connection at the back.
Causes, most likely first on this machine
- Supply line frozen in an unheated run — First in this setting. A line crossing a cold garage or a crawl space freezes before anything inside the cabinet does, and it thaws and refreezes with the weather.
- Shut-off valve closed or partly closed — Second, and the commonest installation fault: the cabinet gets pushed back, the valve gets knocked, and ice stops.
- A crushed or kinked supply line behind the cabinet — Third. Second fridges get shoved into tight spaces and the line pays for it.
- Freezer temperature too warm — Fourth. A freezer holds food safely at zero degrees Fahrenheit or below and an ice maker needs comparable cold to complete a cycle.
- Feeler arm raised or the bin jammed — Fifth, free to check, and it stops production by design rather than by fault.
- Ice maker module or inlet valve — Last, and it is what remains once the water path has been proved.
Check in this order, and why
- Check whether there is a water connection at all — No connection means no ice maker, and the question is settled.
- Trace the supply line and note where it passes through cold space — That is where it freezes, and it is the first thing to check in winter.
- Check the shut-off valve is fully open — One turn, and it is the commonest single cause.
- Put a thermometer in the freezer section — A warm freezer explains poor ice with nothing faulty.
What an owner can safely check
- Confirm the ice maker is switched on and the feeler arm is down — Free, and a common answer.
About 5 min
- Follow the supply line to its valve and open it fully — Look for kinks where the cabinet was pushed back.
Tools: torchAbout 20 min
- Insulate or reroute any section of line crossing an unheated space — This is the fix that stops it happening every winter.
Tools: pipe insulationAbout 45 min
- Put a thermometer in the freezer overnight — Zero degrees Fahrenheit or below is what the ice maker needs.
Tools: thermometerAbout 15 min
- Empty and refit the ice bin, and discard fused ice — Fused ice in a rarely used bin is normal, not a fault.
About 10 min
- STOP HERE before thawing a line with heat or removing the module — Heat near plastic and live work behind a panel are both technician jobs.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel - a capacitor can hold a charge after the power is off. A second fridge is often on an extension lead in a garage: switch off at the breaker rather than trusting a socket switch, and keep water away from the lead. Never chip frost off a cooling plate with anything metal - the tubing behind it is thin and a puncture ends the appliance.
When to call a technician
Call when water demonstrably reaches the cabinet, the freezer is properly cold and the mould still stays dry - that leaves the inlet valve or the module. Call a plumber instead for a supply line that freezes every winter, because the fix is insulation and routing rather than anything inside the appliance. Do not replace the ice maker before the water path is proved: fed no water, a new one performs exactly as the old one did.
Nearest pages of this class
What this page does not cover
This page is written for the overflow or second refrigerator class, not for one family or model line. Where a brand- or model-specific page exists for your unit it is the more specific answer and it is linked above, so go there first if your machine is named. What is deliberately not here: compressor and relay part numbers, thermostat calibration figures, refrigerant charge and shelf dimensions, all of which differ by family and belong on the page for that family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
