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.
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.