Heater Relay Fault
The F03 error code means the control board has detected a fault with the relay that controls the heating element. The relay is either stuck closed (heater always on) or stuck open (heater never activates).
~5%
DIY Fixable
$250-500
Typical Repair Cost
1-3 hrs
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. A relay fault means the heater may run uncontrolled (fire risk) or not at all. This is a safety-critical code — do not use the dryer until professionally inspected.
Can I reset the code?
Yes. Yes, but only as a test. If F03 returns or the dryer overheats, stop immediately. A welded relay will not fix itself.
When to stop immediately?
Stop if you notice: F03 returns after reset, The dryer overheats.
Symptoms You May Notice
Dryer overheats
If the relay is stuck closed, the heater runs non-stop
No heat at all
If the relay is stuck open, the heater never activates
F03 at startup
The board runs a relay self-test before starting
Thermal fuse may trip
Overheating from a stuck relay can trip the safety fuse
Possible Causes
Stuck Relay on Control Board
The relay contacts have welded together (stuck closed) or the coil has failed (stuck open).
Requires ProfessionalPower Surge Damage
A voltage spike has damaged the relay or its driver circuit.
Requires ProfessionalHeater Element Short
A shorted heater element caused excessive current through the relay, welding it.
Requires ProfessionalBoard Trace Damage
The PCB traces around the relay have burned due to overcurrent.
Requires ProfessionalTransient Glitch
A one-time power disturbance may cause a false F03.
DIY PossibleSafe Checks You Can Do
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1
Power Reset
Turn off at mains for 15 minutes. A stuck relay may release when fully de-energized.
15 minutes gives capacitors time to fully discharge.
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2
Check for Overheating Signs
Open the dryer door. Does it feel excessively hot inside? Is there a burning smell?
If yes, the relay may have been stuck closed — do not restart.
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3
Test After Reset
Run a short cycle on low heat. Monitor temperature — the dryer should heat and then stop when target is reached.
If the dryer overheats or does not heat at all, the relay has failed.
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4
Check Breaker
If the heater shorted, it may have tripped the household breaker.
A tripped breaker alongside F03 confirms a serious electrical fault.
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5
Do Not Ignore
F03 is a safety-critical code. If it persists, do not continue using the dryer.
A stuck-on heater is a fire risk.
When to Call a Professional
Contact a qualified Miele technician if:
- Relay stuck closed (always heating)
- Relay stuck open (never heating)
- PCB burn marks near relay
- Heater element shorted
- Under warranty
Need Professional Help?
Find qualified Miele technicians in your area for proper diagnostics and repair.
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