Ac fan not working

dougrainer wrote:
The ONLY things you have NOT changed is the Wall tstat and the Main upper control board. Odds are if you remove the cover on the upper control board you will find the problem. Genset or line voltage is NOT your problem. Doug

I'd be a-getting that cover off. Apparently these boards or connections to them can fail in a visible way. I read all Doug's posts and his suggestions turn out to be spot-on. Doug says what's wrong, might as well order parts...

I haven't read where you have checked the voltage at the fan motor. Because the fan can run separate of the compressor and the only thing you say you heard "humming" is the compressor then you probably don't have power there. Verify that, then it would be in the control board which controls the fan separately via the fan switch on the thermostat or in unison with the compressor when in the cooling position.

IF you have a wall tstat. You have replaced almost ALL the components for the Fan operation. The ONLY things you have NOT changed is the Wall tstat and the Main upper control board. Odds are if you remove the cover on the upper control board you will find the problem. Genset or line voltage is NOT your problem. Doug

j-d wrote:
Is this a 30- or 50-Amp Coach? Is there some kind of "load shedding" device?
I ask because this A/C is acting like my neighbor's house unit did, when one leg of the 240-VAC AC power supply went out.

So, with that in mind, what is the Voltage at the A/C when it's trying to start?

And, as you check circuits, you'll verify the Hot Side/Black wire connections at Shore Tie, Breaker Panel, etc. Pay equal attention to the Neutral Side/White wire connections!

Finally, any "punch down" junction box is suspect.

It’s a 50 amp Coach
The front AC starts and runs fine. I have not tested the shore power but will tomorrow
I even unplugged for the shore power and ran just the generator
And it still will not start.

Is this a 30- or 50-Amp Coach? Is there some kind of "load shedding" device?
I ask because this A/C is acting like my neighbor's house unit did, when one leg of the 240-VAC AC power supply went out.

So, with that in mind, what is the Voltage at the A/C when it's trying to start?

And, as you check circuits, you'll verify the Hot Side/Black wire connections at Shore Tie, Breaker Panel, etc. Pay equal attention to the Neutral Side/White wire connections!

Finally, any "punch down" junction box is suspect.

wa8yxm wrote:
Well he did say it HUMS. so I'm assuming power

If it spins easily, And it has power there are really only three suspects

1: The starting cap (you replaced it but did you get the right one and was it good)
2: The wiring (did you hook it up properly)
3: THe motor.. Start winding burned out.

In the last case spinningh it with power applied (CAUTION DANGER) will start it.. however note words CAUTION DANGER. do not turn fingers into salami and slice,.

Yep I replaced both caps and made sure they was wired back up right
I took the old ones out and took pictures just to make sure it was right
I’ve tried spinning it with the power on still no go I wonder if it’s the control box
The fan a few days before it stopped working was making a odd sound
And my wife said a few days later she went into the room and the fan was not working and the ac unit was just humming.
So I replaced the fan and both caps and still won’t go.

Well he did say it HUMS. so I'm assuming power

If it spins easily, And it has power there are really only three suspects

1: The starting cap (you replaced it but did you get the right one and was it good)
2: The wiring (did you hook it up properly)
3: THe motor.. Start winding burned out.

In the last case spinningh it with power applied (CAUTION DANGER) will start it.. however note words CAUTION DANGER. do not turn fingers into salami and slice,.

MEXICOWANDERER wrote:
How about power AFTER the switch? Am I missing something? How many volts are getting to the motor THEN returning to neutral? Do these motors use a starting contactor?

No contactor used with this type AC unit. It's basically a window AC on your roof. But it is important to know if there is 120 volts to the motor and if so then it's a bad motor. If no voltage then go to the control board.

How about power AFTER the switch? Am I missing something? How many volts are getting to the motor THEN returning to neutral? Do these motors use a starting contactor?

wa8yxm wrote:
Make sure you can turn the fan power OFF by hand

Yep it spins very easy with the power off