Dryer stops heating and displays F04 during a cycle.

Safety first: Unplug the dryer. Heating circuits operate at mains voltage and can cause severe shock.

• Visual inspection:
  • Remove the rear panel to access the heater assembly.
  • Inspect the heater terminals and wiring for burns or loose connections.
  • Check the high-limit thermostat and thermal cut-out mounted on the heater housing.
• Check continuity (if possible):
  • Test the heating element for continuity; an open circuit indicates a failed element.
  • Test the high-limit thermostat and thermal cut-out; they should show continuity at room temperature.
• Resettable thermostats: Some models use resettable safety thermostats. If present, press the small reset button on the thermostat once the unit is cool.
• Control board relay: If the heater and thermostats are good, the heater relay on the main PCB may be defective. Look for burnt relay contacts or tracks.
• After checks: Reassemble, restore power, and run a short warm cycle. If F04 returns, plan to replace the heater assembly or main control board as indicated by your tests.

Warning: Do not bypass thermostats or thermal cut-outs. This is a serious fire hazard.