AC not cooling on HI

[Scott'n'Wendy]

A couple days ago, I had the trailer AC set to Cool/HI Auto. Was running fine. Later in the day I went in and noticed the temp at 28*C and I had the tstat set at 24*C and the AC was not running. Cycled the tstat through OFF and back to Cool/Hi Auto. I think I heard a click in the area of the AC at the other end of the trailer. But that's it. So I cycled the tstat to off again and set it to Cool/Lo Auto. Worked fine. I didn't have time to get into it then but will later today I hope. (Retired and no free time...lol)
I've never had to work on any of my RV AC's. These symptoms sound familiar to anyone?

On edit, I'm plugged into a 15a cct next to my garage.

[Country Campers]

I would recommend low fan on 15 amp power. I have done this at home and camping with no issues. Also if it is humid Hi Auto does not work well, again low fan works best for me. I think what happens when on Auto and 15 amp is the motor heats up or the compressor and does not want to start on the low amp power, but that is just an opinion with no real electrical facts to substantiate that.

Brian

[Scott'n'Wendy]

I would recommend low fan on 15 amp power. I have done this at home and camping with no issues. Also if it is humid Hi Auto does not work well, again low fan works best for me. I think what happens when on Auto and 15 amp is the motor heats up or the compressor and does not want to start on the low amp power, but that is just an opinion with no real electrical facts to substantiate that.

Brian

I thought it would trip the 15a breaker if it needed more juice.
In the interest of troubleshooting...I will plug it into 30a. I will have to make up a plug first though...and open up the panel....run a wire...
Then see what happens.

[Scott'n'Wendy]

Well....the fan doesn't run on hi without a/c....
Now I'm thinking wire connection...

[Jlawles2]

Pull the stat off the wall and check the connections there. I believe several members here have had that issue. I also recall someone having an issue of low being hi and hi being low. Wiring on the back of the stat was backwards.

[Scott'n'Wendy]

Well, finally had some time to look at this issue. So I found a tstat manual - wasn't one in my trailer papers. Attached a copy below. Then I removed 120vac from the trailer. Left the 12vdc on for testing.
Next I removed the inside cover off the ceiling so I could access the control box and look for loose or broken wires. Didn't find any. So then I selected Low Fan on the tstat and I could hear a relay click at the control box. OK, good. Then I selected shut off the tstat then selected Hi Fan. No click. So...I say to myself...control issue, not motor/caps etc. So I removed the tstat from the wall so I could put my meter on the connections. GL is fan low and GH is fan Hi. When on low there was 12vdc at the GL terminal. And there was 12vdc at the GH terminal when Fan Hi was selected. So the tstat is good. (-ve lead on terminal 'B' and +ve lead on the terminal you are checking)
Next check if the 12vdc for Fan Hi makes it to the control box. Do do this I needed to pull the quick disconnect terminals down a bit. They were VERY tight!. But when I moved the GH terminal on the control box....a relay clicked!
I thought it felt like a tight connection....but I caused the action of the relay by moving it.
So I re-applied 120vac and the unit works now on Hi and Low. Tried to make it fail by wiggling the GH wire but seems to be solid now.

Go figure...I like to find more definitive reasons for faults...but I'll take it. Didn't cost me anything but a little time.

[Jlawles2]

See if you can het a better look at that GH terminal. I wonder if it was improperly installed (like they missed the slot as I have seen this before). Moving it caused the connection to get better as it may have been dusty.

[Country Campers]

We seen a similar issue last year at the National Rally. The terminal connection on the board became faulty, we are guessing that it was from pushing the wire connection on as it was pretty tight.

Brian