2012 Keystone Alpine Thermostat Blank screen

[Blakesgst]

--UPdate--

----So after 14 hours of a blank screen. I unplugged all the rj 11 connectors at the ac units on the roof and re plugged them in, then found what appears to be the coupler in the bedroom ceiling where the ducts are, unplugged that and re plugged it in. I then went over to the thermostat on the wall and now it has a very dim blue screen, no info or numbers though. I removed it from the wall, unplugged the rj 11 there, held down the zone and mode button to reset, waited 1 minute, plugged it back in and now its working. Gremlins? After reading a bit more it sounds like the dometic thermostats are kind of buggy, should i consider replacing it and if so is there a plug and play unit of another brand?----

Hi Everyone,

I'm having what seems to be a common issue, last night my thermostat screen went blank and my ac units shut off. After reading through a few older posts it sounds like the most common issue is the communications wire from the thermostat to one of the ac units, that's apparently where the thermostat gets its power. I have pulled the covers off both ac units on my roof and also the access panel to expose the board but, I don't see where the grey wire from the thermostat plugs into either of the boards. Each unit has 2 similar looking phone plugs which are black in color, the wire at the thermostat is grey. Anyone able to tell me where i can find this one particular plug connection? It sounds like its suppose to be on the "front unit" which is over the bedroom correct? The wiring diagram in the manuals kind of looks like there might be a coupler someplace before the ac units but I am not sure where that might be.

This issue happened last week for about 10 minutes and then everything was fine.

I've reset breakers inside the trailer and the main 30 amp power I'm running off of currently as well several times.

Any help is appreciated, its suppose to be 90 for the next few days and I'm hoping to get this resolved asap.

Thanks in advance,

Blake

[wiredgeorge]

You do know that if you have 50A service and run off a 30A plug, you probably should not be trying to use two A/C units? There isn't enough power. Might be or might not be part of your issue.

[Blakesgst]

Originally Posted by wiredgeorge

You do know that if you have 50A service and run off a 30A plug, you probably should not be trying to use two A/C units? There isn't enough power. Might be or might not be part of your issue.

That's correct, I typically only run 1 at a time. I believe 30 amp is enough for them to run at the same time, just not start up at the same time.

Thanks,

Blake

[ChuckS]

The OEM thermostat in your Alpine is most likely just fine... It gets its 12 volts DC power from the Zone 1 A/C roof unit control module...

If this is a CCC2 Dometic thermostat.. On the 2012 not sure what you have.. the 2013s and above used the CCC2 multi zone thermostat...

The 12 volts DC is fed down from the roof Zone 1 control module to the thermostat... Remove the 4 wire line and measure the DC voltage present to the thermostat on that line

If its erratic or low voltage then that's your issue...

If this is an older thermostat then look at the gateway connections from it to thermostat....