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Author Topic: Dometic AC Will Only Run On High Fan Speed  (Read 590 times)

gintera563

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Dometic AC Will Only Run On High Fan Speed
« on: November 09, 2017, 08:16:40 PM »
Hello Everyone! For about the last two years the AC in our 2014 Puma travel trailer will only operate on high fan speed. As long as we start the fan on high then switch over to cool the AC run perfect and cools the camper as it should. If we switch it to low or auto, we can hear a click in the control board (above the filter inside the camper) but the fan will shut off. If we try to start it on low or auto, we get the same click and no start. If we wait a few seconds, we can hear the compressor humming but no fan. I have tried switching out the thermostat but that didn't help. I'm wondering where to go from here... Control board, fan motor, or something else?? Any help would be great!

Rene T

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #1 on: November 09, 2017, 08:30:15 PM »
Welcome to the forum. Just a little tip. You only need to post your question in one section. If the forum staff feels that your post would get better coverage or exposure in another section, they'll move it.
Rene, Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

gintera563

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #2 on: November 09, 2017, 08:31:16 PM »
That is very helpful to know, thanks!

56safari

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #3 on: November 09, 2017, 08:51:42 PM »
byrantrv.com has a diagnostic service manual for the Duotherm AC units that will help if you have that type AC unit.

Fan speed is typically controlled by a resistor or through a control  board.  It is also possible that the motor has separate windings for each speed,  In any case you'll need the manufacturer and model number to find the correct wiring diagram or diagnostic manual.

Good luck!
Jim & Lin
1999 Rexhall Aerbus

John From Detroit

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #4 on: November 10, 2017, 07:40:40 AM »
120 volt fans typically use the multi-winding method.

Possible issues
Bad relay (The clicker)
Bad wire/connection
Bad low speed winding


Suggestion:  Many people report issues with A/C icing up when run on LOW.. Do not use LOW. Use High, that's what I do. Even though low works (I do admit to using LOW fan from time to time.. Just fan not cool)
Nothing adds excitement like something that is none of your business
My Home is where I park it.

gintera563

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #5 on: January 14, 2018, 04:21:25 PM »
I have now tried a new thermostat, control board, and checked the wire connections. I'm guessing the next step is a new fan??

Willandgiselarv

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #6 on: January 14, 2018, 07:32:01 PM »
I have the same issue with my rear ac...
Haven't gotten on roof to inspect most likely will order a new fan motor with the capacitor..
Low speed used to work but was clicking badly, now it's completely dead and only high speed works.
2004 GB. Bellagio 38ft  3126E Allison 3060
2015 Jeep Cherokee Trailhawk

gintera563

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #7 on: January 22, 2018, 05:56:24 PM »
I think I'm going to try a new fan motor next...

Willandgiselarv

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Re: Dometic AC Will Only Run On High Fan Speed
« Reply #8 on: January 29, 2018, 07:16:21 PM »
Let me know which part# of fan assembly you ordered and if it fixed the problem.
I havenít gotten around to fix it because the a/c works and the weather permits me to wait.
Thanks
2004 GB. Bellagio 38ft  3126E Allison 3060
2015 Jeep Cherokee Trailhawk

 

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