Er DH (also shown as dH) on an LG refrigerator is a defrost error — the system that periodically melts frost off the evaporator coil isn't completing, so ice builds up, blocks airflow, and the fridge (and freezer) start warming. It's a well-defined fault that points at the defrost circuit. Here's how a tech works it.
The most common cause of Er DH. The defrost heater warms the evaporator coil to melt frost; when it burns out (goes open), frost never clears, ice builds, and the fridge warms.
Check it: A tech ohms the defrost heater — an open reading confirms it. It's an affordable, common replacement.
A bi-metal thermostat or thermal fuse in the defrost circuit can fail open, cutting the heater even though the heater itself is fine.
Check it: A tech checks these for continuity alongside the heater — inexpensive parts.
The sensor that tells the control the coil temperature can fail, so the control never runs (or never confirms) a proper defrost.
Check it: A tech ohms the defrost thermistor against spec.
A broken connector to the defrost components, or the control board, can also throw Er DH.
Check it: If the heater, thermostat, and sensor test good, a tech checks the wiring and control.
Repair — the defrost heater, thermostat, fuse, and sensor are all affordable parts, far below a new fridge. The key is fixing the defrost circuit so ice stops building and the fridge cools normally again.
Last week a customer kept their appliance instead of replacing it — they installed the part themselves with the exact one we shipped, after a $50 Quick Check told them precisely what they needed. That's the whole idea: honest answer, right part, no upsell.
In Middle Tennessee or the Baton Rouge area? We'll come to you, same-day. Anywhere else in the U.S.? Send a 10-second video, a real technician tells you exactly what's wrong for $50 (credited toward the repair), and we ship you the exact part. 24/7 — text, call, or upload anytime.
It's a defrost error — the defrost heater or its circuit isn't melting frost off the coil, so ice builds up and the fridge warms. Usually the defrost heater, thermostat/fuse, or sensor.
The diagnosis (ohming the heater, thermostat, and sensor behind the freezer panel on 120V wiring) and the parts replacement are really a tech job. You can help by clearing food and letting it defrost, but the repair itself needs a technician.
It lets ice build and the fridge warm, which can spoil food — so it's worth fixing promptly. The parts are affordable, and your $50 Quick Check credits toward the repair.