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Duo-Therm A/C unit suddenly quit

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I have a 2003 Starcraft Aruba travel trailer with a Duo-Therm A/C unit with a 3107541.009 control unit. Unit has always worked great, but occasionally after setting up at the campsite, when I would turn on the A/C, it would not come on. I would remove the ceiling cover and jiggle the clump of wires, and it would come on and stay on for the duration of the trip. So today I decided to open up the cover and check all the wires for a loose wirenut. Turned the unit on, and it started right up. Turned it off to pull out the wires. Discovered a small red wire that looks like it came out of a wirenut. I have no idea where this wire should connect to, and now the A/C will not come on. There is a blue/white wire with a wirenut on it, but no other wire with it. Connect the 2- nothing. The red wire in question comes from a hole on the ceiling framing that also has a little white wire, as well as 2 large red wires and 2 large white wires, green wire, and the wires to the thermostat. When I touch the little red mystery wire to the 2 large red wires, the fan to the unit comes on, but not the condenser. This also happens when I touch the red wire to a wirenut that connects a white wire and a blue/white wire. Touch the wire to all other wirenutted connections, and nothing happens. When I switch the unit from "Off" to "Cool" and back, the condense clicks, but does not come on. Unit was working great until I pulled the wires out to examine them and discovered the mystery wire with a wirenut-ready end connected to nothing. Any thoughts on this?

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Welcome to the Escapee forums! I'm sorry to hear that it took problems with the air conditioner to bring you here but we will do all we are able to assist and we do hope that you become an active contributor to our group.


The first thing that I suggest you do is to visit the website of Bryant RV and download a copy of the service manual for the air conditioner that you have. While I'm far from being an air conditioner expert, I did spend 40 years as an electrical/mechanical service tech. and I strongly discourage the touching together of wires that you don't know what they do. It is very possible that you may cause other problems beyond what you now have by doing this. Most RV a/c units use 12V-dc for their control circuitry and 120V-ac for the power to run the unit. If you should accidentally apply 120V-ac to a 12V-dc circuit you re very likely to do serious damage. The proper service manual should give you information about where those leads go.


Those small wires are probably from the thermostat and if they are they most likely will be 12V. If you have a quality meter you should take some voltage readings also. We really need more information to be able to do any more than guess at what your problem may be.

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So early Monday morning I'm leaving for work, and I notice that the floodflight on my garage is out. Figured that a breaker in the panel in the garage was tripped, which I knew was also feeding the receptical that my camper is plugged into all the time. No time to check then, but I can when I come home for lunch. Get home for lunch, reset the breaker, and then go into the camper to check. Turn the switch from "Off" to Cool"- comes right on! Have checked several times yesterday and today, and it comes on every time. The floodlight bulb was burned out, so I guess that's what tripped the breaker when it blew out, and it looks like the problem was nothing more than no 120v to the camper and everything running off of the battery. All I know is that the wires are put back, the cover is on, and I'm leaving it alone at this point since all connections are tight and the unit is working.

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