EC33

Sub-Zero Anti‑Condensation Heater Circuit Fault

Wine cooler displays EC33 and may have issues with the mullion or frame heater; condensation may form around door frame.

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Failed mullion/frame heater, Open heater wiring, Faulty heater relay on control board, Incorrect heater configuration on replacement board

How to Fix / Troubleshooting

Safety first: Disconnect power before accessing door frame or mullion wiring. Surfaces may be sharp.

Step 1 – Confirm condensation issue

Check for moisture or sweating around the door frame or mullion area.
If condensation is present and EC33 is displayed, the heater circuit is likely not operating.

Step 2 – Inspect wiring

Access the mullion or frame area as per your model’s service instructions.
Inspect heater wiring for breaks, pinched sections, or disconnected connectors.

Step 3 – Heater replacement

If the heater element is open (no continuity) or physically damaged, replace it with the correct Sub‑Zero mullion/frame heater.

Step 4 – Control board check

If the heater and wiring are intact, the control board’s heater relay may be faulty.
Board replacement should be performed by a qualified technician.

Repair Difficulty

Hard 4/5

Required Part

Mullion Heater

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