Whirlpool · Microwave Serious

F6 — Microwave Relay Failure

The relay that switches the high-voltage transformer / inverter has failed or is being commanded incorrectly. The unit usually won't heat or will heat unexpectedly.

Keep using it?
Limited use only
DIY difficulty
Hard
Verified against
applianceaid.com ↗

How to fix it

  1. Stop using the microwave. A welded HV relay is a real safety concern.
  2. Power down at the breaker for at least 1 minute.
  3. If trained on microwave HV: unplug, discharge the HV capacitor, inspect the control board for a burnt relay or scorched PCB trace.
  4. Repair the harness if pinched; otherwise the fix is to replace the appliance control board (the relay isn't typically socketed).
  5. Untrained DIY should call a qualified microwave service tech for F6.

Why it happens

Typical signs: F6 on the display · Microwave fan and light work but no heat · Audible chatter from inside before the code appears

  • Failed power relay on the control board The relay contacts weld or burn open after years of cycling.
  • Shorted wiring to the relay A pinched harness can fault the relay drive circuit.
  • Failed appliance control board When the relay is integral to the board, the whole ACU is replaced.

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.

  • Whirlpool microwave control board Common replacement
    Amazon →

More Whirlpool microwave codes

AccuPop Fail AccuPop Fail — Popcorn Sensor Fault Demo Demo Mode — Not Heating Door Door / Open Door Closed — Safety Reminder F1E4 F1E4 — Appliance Manager or Power Relay Fault F1E5 F1E5 — Inverter Internal Fault F2 F2 — Keypad / Control Fault

All Whirlpool codes → All microwave codes →

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: applianceaid.com.