Frigidaire FFRG4120SW 6.7 cu ft Front Load Gas Dryer E66 Error Fix: Heater Relay Stuck — Multiple Trips

Error code E66 on the Frigidaire FFRG4120SW 6.7 cu ft Front Load Gas Dryer means: Heater Relay Stuck — Multiple Trips. The heater relay has been detected as stuck on during multiple heating cycles. The control board has shut down heating as a safety precaution. Similar to E62 but detected across multiple cycles. The control board must be replaced. Inspect the heating element and thermal devices before installing a new control board to prevent the same failure.

The most successful fix is "Replace Control Board After Inspecting Heating Element and Thermal Devices" (hard difficulty, ~90 minutes). Estimated DIY cost: $100-$150. HomeMD has 2 community-ranked fixes for this error.

This error is rated critical severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Yes — the top-ranked community fix ("Replace Control Board After Inspecting Heating Element and Thermal Devices") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

DIY cost: $100-$150. Professional repair typically costs $250-$350. Many homeowners save money by trying the top-ranked community fix first.

The Frigidaire FFRG4120SW 6.7 cu ft Front Load Gas Dryer has 8 other known error codes, including: E4A (Inlet Thermistor Open or Shorted), E4B (Outlet Thermistor Open or Shorted), E5B (Door Switch Open — Door Not Closed), E5C (Motor Start Failure), E61 (Heater Relay Not Closing), and 3 more.

Error code E66 also appears on 5 other Frigidaire models: FCED4900HW 8.0 cu ft Electric Dryer with Quick Dry, FCGD4900HW 8.0 cu ft Gas Dryer with Quick Dry, FFRE4120SW 7.0 cu ft Electric Dryer with Wrinkle Shield and Sensor Dry, FFRE4120SW2 6.7 cu ft Front Load Electric Dryer, GLTE2940FS 5.8 cu ft Gallery Electric Dryer. The fix may vary by model, so check each model's specific page for tailored repair steps.