LG · Microwave Moderate

F-5 — Damper Switch Error

F-5 means the control detected a fault with the damper switch. This is not a high-voltage, magnetron, or capacitor fault — that association comes from other brands' fault-code tables and doesn't apply to LG's F-5.

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
lg.com ↗

How to fix it

  1. Unplug the microwave and let it sit at least 5 minutes before opening the cabinet.
  2. Locate the damper switch and damper mechanism — position is model-specific, so check your model's service sheet.
  3. Inspect the damper for anything blocking it from moving freely and clear any obstruction.
  4. Test the damper switch for continuity in both positions; replace it if it doesn't switch cleanly.
  5. Inspect the wiring and connector at the switch; reseat or repair as needed.
  6. Reassemble and test a cook cycle.

Why it happens

Typical signs: F-5 on display · Microwave may not start a cook cycle or shuts down mid-cycle · Damper or vent mechanism may be visibly stuck, misaligned, or not moving freely

  • Faulty damper switch The switch that senses the damper/vent position has failed or is out of adjustment.
  • Damper mechanism binding The physical damper is stuck, obstructed, or misaligned, so it can't reach the position the switch expects.
  • Wiring or connector fault at the switch A loose or damaged connector prevents the control from reading the switch correctly.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • LG microwave damper switch Common replacement
    Amazon →

More LG microwave codes

DOOR DOOR / Door Error — Door switch / interlock fault F-1 F-1 — Main Control Board Fault F-2 F-2 — Thermistor / Temperature Out of Range F-3 F-3 — Key short / specific button stuck F-4 F-4 — Humidity / steam sensor fault F19 F19 — Inverter / High-Voltage Fault

All LG codes → All microwave codes →

Frequently asked questions

What does the F-5 code mean on a LG microwave?

F-5 means the control detected a fault with the damper switch. This is not a high-voltage, magnetron, or capacitor fault — that association comes from other brands' fault-code tables and doesn't apply to LG's F-5.

What causes the F-5 code on a LG microwave?

Faulty damper switch: The switch that senses the damper/vent position has failed or is out of adjustment. Damper mechanism binding: The physical damper is stuck, obstructed, or misaligned, so it can't reach the position the switch expects. Wiring or connector fault at the switch: A loose or damaged connector prevents the control from reading the switch correctly.

Is it safe to keep using a LG microwave with a F-5 error?

Yes, with caution. This is rated a moderate-severity fault.

How do I fix F-5 on a LG microwave?

Unplug the microwave and let it sit at least 5 minutes before opening the cabinet. Locate the damper switch and damper mechanism — position is model-specific, so check your model's service sheet. Inspect the damper for anything blocking it from moving freely and clear any obstruction.

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.