Air conditioner does nothing

Papadod7 · 05-03-2022, 10:59 AM

The A/C unit on my 2007 Keystone Copper Canyon does nothing when I turn it on. I can hear the thermostat click as I adjust the temperature, but the unit never makes a sound. Nothing. The thermostat works great for the furnace, and all of our other appliances work. The breaker is on at shore power and inside the trailer. What could the issue be?

**flybouy** · 05-03-2022, 11:17 AM

Couple of questions first. Did it work previously? If it did, any unusual noises or events the last time it ran? When you turn it on now you say you hear the t'stat click but is there any clicking or other noise comming from the a/c unit? Have you tried turning the stat to fan only, or manual? Try turning fan speed from low to high?

**chuckster57** · 05-03-2022, 11:17 AM

Make sure you have 11VAC going out of the breaker. Then remove the ceiling assembly, and you should see a junction box or the control box with Romex going into it.

UN PLUG from shore power, get the control box loose and open it up. Look at the AC wires and make sure all the connections are solid. With the power still off reach up and spin the fan. If it spins, then it’s time to start testing with a multimeter.

How comfortable are you working with a multimeter and possible energized wires?

wiredgeorge · 05-03-2022, 12:08 PM

Perhaps knowing the type of thermostat and A/C brand and model might help? Is this a Duotherm Dometic Brisk or Brisk II? Is the thermostat analog?

Papadod7 · 05-03-2022, 04:59 PM

Thank you all.

I adjusted the controls to every possible configuration, and still nothing. Opened up the AC box, all the fuses are good and wires connected. Is there an on off or restart switch somewhere that I am missing?

What do I check on the multimeter?

**chuckster57** · 05-03-2022, 05:23 PM

At this point we need to know brand/model of AC and thermostat.

Papadod7 · 05-07-2022, 09:09 AM

Hey guys,

The AC unit on my RV is a dometic duo-therm.

Is the same thermostat used for both the furnace and the AC unit?

**chuckster57** · 05-07-2022, 09:13 AM

Quote:

Originally Posted by Papadod7

Hey guys,

The AC unit on my RV is a dometic duo-therm.

Is the same thermostat used for both the furnace and the AC unit?

If you have 2 AC units and 2 thermostats, only 1 will control the furnace. Can you post a pic of the thermostat?

**flybouy** · 05-07-2022, 10:12 AM

I think most t'stats from that era would have a switch for "heat, cool, off" and a swich for the fan "high, low or auto". High and low is a manual mode that makes the a/c fan continually and auto the a/c fan only runs if the compressor runs. I turn our Stat to fan high and cool. If the stat works the furnace then 12 vdc is getting to the stat.

Next step, see if the 12 vdc is comming out of the stat to the a/c unit. If you have power from the stat at the a/c and you have 120 vac at the air conditioner then I'd suspect a bad relay in the a/c unit. If the compressor failed the fan would still run. If the fan failed the compressor would still run. Both are 120 vac and controlled by 12 vdc.

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