Thermostat Problem Againe

[Hawkpat]

Back in February Dometic thermostat went blank and ac quit running. After checking electrical for about 15 minutes it came back on (by itself) and worked through mid April. On our last night before coming home it went blank again and stayed that way.

I took it into the shop and when they removed from wall and hooked back up it worked fine. When I picked up camper I checked with them and it was fine.

Today we were going to go on a trip and when I hooked up the camper I thought I better check the thermostat and when I did it was dead again. Called repair shop and told them what was occurring and they had me bring it in (about 25 miles). When I arrived I went and checked it and it came on.

Really confused but can’t take a chance on going since if it doesn’t come on. Service manager scratched his head but said they’d look at it. Any ideas???

[cpaulsen]

Similar problem with mine...….contacted Dometic and they sent me new one free of charge.

[DQDick]

Based on what you've done, if it's not the thermostat, look at the connection where the thermostat cable connects to the AC.

[ChuckS]

It could be one of several items causing this.....

.... bad CCC2 thermostat ... cracked solder point on its circuit board
.... bad telephone connection plug coming to CCC2
... bad telephone cable line that runs from air conditioner Electronic control module
... intermittent 12’ volt DC power line to ECM

[WeBeFulltime]

"Dometic thermostat" can cover a broad range. We have owned 3 different Montanas and all 3 had different Dometic thermostats. Might be helpful to know more about YOUR Montana and what type Dometic thermostat it has.

[Hawkpat]

It’s a Montana 3400 and the dometic ccc2 thermostat

[SuzanneH]

A quick phone call to Dometic will get one coming your way. They are very pleasant on the phone and only takes a minute.

[Skw774]

replaced both of mine-no more issues

[Rsmarlow82]

These thermostats are in my opinion are not dependable and I would change it out Ours switches from cooling to heat pump if you touch temp up or down
Our service tech recommended going to a "non" touch type unit, that actually have switches and mechanical connections

Yeah, they will send you a new one, but our tech said changes are you will get another piece of junk lol

[Don Hopkins]

Okay, on my 14 3582, replaced thermostat, then main circuit board, then com cable, which fixed most problems. Furnace still didn't always light when it came on. Tech finally replaced the ground wire, and low and behold, all finally working. Oh, and did I mention that was after replacing zone 1 ac as well, when it was the com cable the whole time. CW diagnosis in Grand Rapids Mi. So a year later, all is well. Lol, needless to say, cw did not fix anything, they didn't even know unit had 2 ac units. So they fixed nothing.

[scarpent]

We have a 2018 FL3730 and have had similar problems with both thermostats. CW replaced both of them a month after purchasing the Montana. 6 months later both were giving me same trouble again. Contacted Dometic direct and complained about the problem. They sent me two new thermostats and new control cards for the AC units with out any costs. First time out this season the front AC was causing problems again. Start it up, runs for awhile, changes speed from high to low to high several times then just dies. The only way to get it going again was to reset the thermostat. Did this several times but would continue to have the same problems as before. The back AC seems to be fixed. Contacted Dometic again. They sent me another thermostat and control card again. Replace both the thermostat and card, still had the same problem the next trip out. Finally took it back to CW. They got on the phone with Dometic, they finally thought there was a communication problem with wire interference from other cables. CW was told to move some cables in the AC unit away from the thermostat wiring to see if that would take care of the problem. Have run the AC for two weeks without an issue. Will see if it continues. Hope this helps.

Sorry for the long reply.

[azwiz]

what number did you use for Dometic ?
thanks
Steve

[scarpent]

Originally Posted by azwiz

what number did you use for Dometic ?
thanks
Steve

(574) 294-2511 x2563

I also corresponded with them at this email address:
sarah.newton@dometic.com

[Mikendebbie]

The thermostat for our living area gave me a scare a couple of days ago. We got set up and I set both ACs on high to cool things off. The next day I was going to try the AUTO setting - and the thermostat sort of went dead/ off. I was tapping on it and strange stuff was showing on the display...it was non-responsive. I took the face plate off and clicked it back on - a couple of times and finally it started acting normal. I had no idea what I did or what was wrong. AC has been running fine since...I will not touch it again until we are hooked up and leaving. I think I will call Dometic on Monday and see if they will send us a new one before we head out again in a couple of weeks. The bedroom thermostat has been working fine.

As I was looking at the back side of the face plate, I could not figure out how the thing works. It looked like foam under the button.

When they “send a new one” - is it just the face plate or is it the whole unit?
Also the pic below is the thermostat I have. Is that the same type being discussed in this thread?

I assume there is not an upgrade available or it would have been discussed here (like replacing the toilet with a 320).

[mtlakejim]

One thing for certain, IF your batteries are weak and or the converter has crashed you will have issues with thermostats (ask me how I know). The control/thermostat signal is 12 volt pulled from the camper 12volt system. Personally I realllllllyyyyyyy wish they would add a separate 12volt transformer on the 110 system to power the thermostats as you can't use the AC units without 110 anyway! That way if something went haywire with your 12volt system at least you would still have AC and I really like the two systems being more or less independent of each other anyway.......

[scarpent]

Originally Posted by Mikendebbie

The thermostat for our living area gave me a scare a couple of days ago. We got set up and I set both ACs on high to cool things off. The next day I was going to try the AUTO setting - and the thermostat sort of went dead/ off. I was tapping on it and strange stuff was showing on the display...it was non-responsive. I took the face plate off and clicked it back on - a couple of times and finally it started acting normal. I had no idea what I did or what was wrong. AC has been running fine since...I will not touch it again until we are hooked up and leaving. I think I will call Dometic on Monday and see if they will send us a new one before we head out again in a couple of weeks. The bedroom thermostat has been working fine.

As I was looking at the back side of the face plate, I could not figure out how the thing works. It looked like foam under the button.

When they “send a new one” - is it just the face plate or is it the whole unit?
Also the pic below is the thermostat I have. Is that the same type being discussed in this thread?

I assume there is not an upgrade available or it would have been discussed here (like replacing the toilet with a 320).

The pictured thermostat pictured is the same as I have. When Dometic sent me a new thermostat and control card it was the same as you have and it was a complete thermostat unit. The unit is a capacitance discharge unit which uses the foam backing to work. Not sure how that works. When I had trouble with it I reset the thermostat by taking the face plate off and touching the three contacts at the same time. This resets the electronics.