I have a problem with my air conditioner fan not starting. As seen from the schematic below, when I test for voltage between the brown and black wires, I get 0 V (this is the problem). The indoor unit isn't sending the control signal to turn the fan on. The compressor powers on fine though. When I connect the brown and red wires together (since red is giving power fine), the circuit breaker trips, maybe too much inrush current since motor and compressor turn on together?

I then powered the fan separately and it works (fan or capacitor is not faulty).

  • Could there be a relay or something controlling the fan that's not giving power from brown cable?


  • \$\begingroup\$ You would have to check the indoor unit, possibly posting a picture of the control board. It's probably controlled by a triac and it might have died. \$\endgroup\$ – Damien Feb 26 '19 at 12:37
  • \$\begingroup\$ Can you measure the capacitance of the motor run capacitors? If not, measure the voltage across them when energized? \$\endgroup\$ – winny Feb 26 '19 at 12:42
  • \$\begingroup\$ @winny, I started the motor separately and it turns on and runs. I understand the capacitor is responsible for starting the motor, if it was faulty wouldn't the motor not start ?, thanks \$\endgroup\$ – Deadshot Feb 26 '19 at 12:49
  • \$\begingroup\$ Suggest migrating this to DIY \$\endgroup\$ – brhans Feb 26 '19 at 12:58
  • \$\begingroup\$ Yes, there could be a relay or something that is not giving power from the brown cable> That certainly seems to be the most likely problem. \$\endgroup\$ – Charles Cowie Feb 26 '19 at 13:00

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