F5 Serious Moderate DIY

Frigidaire Microwave F5 — Relay / control output fault

Frigidaire Microwave · Error code F5

What F5 Means

F5 means the control board has detected an internal relay feedback mismatch — a relay (often magnetron, fan, or turntable) did not switch as commanded. Usually a control-board failure.

Symptoms

  • F5 on display
  • Microwave may run but not heat, or fan runs constantly
  • Fault appears shortly after start

Common Causes

1
Failed relay on control board

Stuck or burnt relay contacts on the ERC.

2
Open magnetron or HV components

Loss of expected feedback to the board.

3
Wiring fault to controlled load

Broken wire to fan motor or turntable motor.

How to Fix It

  1. WARNING: Microwave HV capacitors can store a lethal charge — discharge before probing HV components.
  2. Unplug and wait 5 minutes; retry once.
  3. If F5 persists, inspect harness from control board to fan, turntable, and HV transformer for breaks.
  4. Verify magnetron and HV diode are not shorted (ohms test, capacitor discharged).
  5. If HV side checks good, replace the electronic control board.

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.

Common replacement Frigidaire microwave control board View on Amazon→ Common replacement Microwave HV diode View on Amazon→

More Frigidaire Microwave Codes

Child Lock 'Lock' / 'L' — Child lock engaged Cooling Fan 'Cooling Fan' / Fan-runs-after-cooking — Vent fan stuck on Demo 'Demo' / 'd' — Showroom demo mode on door 'door' message — Door not fully closed F1 F1 — Control board / thermistor open F10 F10 — Analog-to-digital / keypad communication error

All Frigidaire codes → All microwave codes →

Verified against manufacturer documentation: frigidaire.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.