Dometic thermostat not working again

[Hawkpat]

I posted a couple of months ago when we were running our ac and the dometic thermostat just went blank and would not respond. It came back on by itself after about 15 minutes and has operated fine since. This morning we turned everything off and travelled and now it will not respond again.

Several posters said it was probably a loose wire behind thermostat. I believe I have a ccc2 thermostat on our 2014 Montana 3400. Question is how do you remove the thermostat to check the wire connections. I pull it from the wall but it doesn’t want to come free. Afraid to make matters worse.

[dlscott185]

If it's like ours, the front panel comes off and there should be some screws inside holding it to the wall. That should be it.

[kc8lvy]

Mine did the same thing. I was able to remove cover on the thermostat then I checked for voltage with my multimeter. You should have 12 volts. I had none. I had to get up on the roof and remove my AC cover and found out that it was a bad wire up there. I just had to resplice it.
Good luck

[Hawkpat]

Thanks for your replies. I was able to pull it off the wall. It was connected by a telephone type jack connection. No clear loose wires. Remaining repair is above my skill level. This is our last night on the road. We have the fireplace and two space heaters so we’ll survive. I’ll take it to the shop when we get home.

[rohrmann]

Above the ceiling panel for each A/C unit, there is a metal box that has the electronics that communicates with the thermostat. On ours, the cable that looks like a phone cable goes to the Zone 1 A/C which is in the living room. From that box, another phone cable runs to the Zone 2 A/C, in the bedroom. The furnace control wiring goes to the Zone 1 box also. The thermostat receives power through the phone cable. So, if the thermostat is good, it's possible that a cable may be bad, or more likely, there could be a problem in one of the control boxes below the A/C's. Our bedroom A/C stopped working years ago, and I discovered the circuit board was covered with corrosion and the connectors the the phone cable connected to were heavily corroded. I replaced the box and everything worked again. This is a photo of the corrosion that I had on that circuit board.