Indoor unit shows E4 and stops; may occur shortly after compressor starts, often in cooling mode.

Safety: Disconnect power at the breaker. The fan blades are sharp; wear gloves.

Steps:

• 1. Check for obstructions: Open the front panel and visually inspect the blower wheel (cross-flow fan). Remove any debris, plastic, or insulation blocking rotation.
• 2. Spin test: Gently rotate the blower wheel by hand. It should spin freely without grinding or tight spots. If stiff, the motor bearings may be failing.
• 3. Access fan motor: Remove the front cover and lower housing as needed to expose the fan motor and its wiring harness.
• 4. Inspect wiring: Check the multi-pin connector from the fan motor to the indoor PCB. Ensure it is fully seated and not burnt. Look for damaged wires.
• 5. Power-on observation (advanced): With covers safely in place but still accessible and using extreme caution, restore power and start the unit. Observe if the fan attempts to start. If it only jerks or does not move, the motor or driver is suspect. Turn power off again before touching anything.
• 6. Replace fan motor if seized or noisy: Remove the blower wheel (usually by loosening a set screw) and unbolt the motor. Install a compatible Airwell indoor fan motor, align the blower wheel, and tighten the set screw.
• 7. PCB check: If a known-good motor still does not run and E4 persists, the indoor PCB fan driver circuit may be defective and require replacement.
• 8. Final test: Reassemble all covers, restore power, and test in cooling mode. Confirm stable fan operation and no E4 code.