Air conditioner fan not starting

[TheRedDevil18]

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?

Any ideas?

 

[Rive]

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

Just because they start you can't be sure jet.

There is no fuse on the brown line, but I'm pretty sure there should be one somewhere (just not in the outdoor unit). Try to find it first and check if it is still OK or not.

 

[russ_watters]

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...

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

Yes. Do you have a wiring diagram for the indoor unit's controller? Can you verify the signal is being sent to the brown wire at the unit? Can you verify the continuity of the brown wire?

This issue may be as simple as a bad control wire or it may be a lot more complicated. The fan may not always run, but might be controlled based on refrigerant pressure, and you may have a bad controller or sensor.

 

[jim hardy]

Where are you ?

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

What did you use to power the fan in that test? 220 or 115 volts?

Have you checked that all three of its wires show at least a few megohms to ground its metal frame ?

Were its red wire internally shorted to frame
and your test setup hooked red to a grounded power conductor (neutral in USA) and black to "hot"
it'd explain your observations
and there'll be an open in the supply to brown wire - fuse or melted relay contact