F8
Trane Indoor Fan Motor Feedback Fault (ECM/Variable-Speed)

Trane air conditioner displays F8 and may shut down due to abnormal fan speed or feedback.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed ECM blower motor, Loose blower harness, Obstructed blower wheel, Faulty indoor control board fan driver

How to Fix / Troubleshooting

Safety first: Turn off power to the air handler or furnace before removing blower access panels.

  • Inspect blower wheel: Check for debris, insulation, or objects lodged in the blower wheel. Remove obstructions and clean dust buildup.
  • Check harness: Ensure the multi-pin ECM motor connector is fully seated and free of corrosion.
  • Spin test: Rotate the blower wheel by hand; it should move freely without scraping.
  • Reset: Restore power and call for cooling. If the motor does not start or starts then stops with F8, the ECM module or motor is likely faulty.

ECM motor replacement requires matching Trane part numbers and programming in some cases. Have a technician perform final diagnosis and replacement.

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Repair Difficulty

Hard 4/5

Required Part

Trane ECM Blower Motor
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