Haier Outdoor Unit Not Starting / Control Signal Failure

Indoor unit powers on but compressor and outdoor fan never start; only fan mode works.

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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

Communication failure between indoor and outdoor, Faulty outdoor PCB, Open circuit in compressor power wiring, Incorrect mode or temperature settings

How to Fix / Troubleshooting

Safety first: Turn off power before inspecting wiring.

  • Check settings: Ensure the unit is set to COOL or HEAT with a target temperature lower (for cool) or higher (for heat) than room temperature.
  • Inspect communication cable: Verify the multi-core cable between indoor and outdoor units is intact and correctly wired.
  • Listen for outdoor relay click: When starting cooling, listen near the outdoor unit for relay operation. No sound may indicate PCB failure.
  • Check outdoor power: Confirm that the outdoor unit is receiving mains power at its terminals.
  • If outdoor still does not start: A technician should test the outdoor PCB and compressor circuit.
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Repair Difficulty

Hard 4/5

Required Part

Outdoor Main Control PCB
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