Keystone Alpine CCC2 wiring

[ChuckS]

21831

1

If your Dometic CCC2 digital thermostat is dead and you have no 12 VDC power up on the air conditioner electronic control modules this might be useful info

2014 Alpine and I’d bet all Alpines with CCC2 thermostat obtain their DC power from the Zone 1 air conditioner electronic control unit. It is hot all the time at the control module even with thermostat off as long as DC power is present. 12 volts DC is then routed over a non standard wired RJ11 telephone cable from control module down to CCC2 thermostat.

In the DC power distribution center the 15 amp fuse labeled “Kitchen” has a green/white wire at fuse bus ... this provides DC power to overhead power vent/fan mounted in the ceiling.

So if fuse is good but thermostat is dead and no DC power is on red/black wires on air conditioner electronic control module on roof this is where I’d start looking for a broken wire

[Dave1962]

I just purchased a 2013 Alpine and found while the wife and I were loading our personal items into it that the thermostat had no power. I spent a couple days off and on checking the wiring diagrams from Dometic but none showed how 12v power was supplied to system, off the battery or through fuse panel. I also tried tracing the RJ11 wires from front air opening and thermostat thinking this was a direct line.

Unfortunately as much as I was wishing it was a fuse my issue I couldn't find any blown fuses so the adventure began. On the installation drawings for the roof air units it always showed the front air as the main, Zone 1, but on my trailer the Zone 1 is the rear which is the bedroom. It took a couple days of confusion as to how this system worked and was wired in which I made quite a few trips up and down the ladder before the proverbial light came on and I realized I was at the wrong end of the wiring. After I opened up the control box on the rear air unit I found there was a constant 12v there so I knew it had to be control wire. I then tested the wires from thermostat and air unit and from front unit to rear and found there was a break in the RJ11 cable from the thermostat to the control box. I had to remove the air unit, light in bedroom and one in the hallway to get access to the cable, wires were all tangled together in roof so I had to pull a small section at a time. When I got the wires fed through and put ends on I connected it and still had no power then I realized that the wiring harness with the air unit had a cross over so I needed straight through connection, same as phone. I cut off the end and crimped on a new end and success.

In the end it looks like the wires were twisted together trough the roof trusses and the weight of the roof air conditioner cut the cable when the trailer went through a pot hole.

Thanks ChuckS for shedding light onto how this system gets the 12v power, I would have been still scratching head over that.

[ChuckS]

Glad you were able to get your thermostat powered up again...

Zone 1 ... usually larger air conditioner unit with a 2 roof system is Always the “master” regarding DC power source as well as how the CCC2 digital thermostat is wired.

One 4 wire cable runs from thermostat to Zone 1 electronic control module (ECM)... if dual AC unit then another runs from Zone 1 to Zone 2 ECM

additionally 1 more 4 wire Line r7ns from Zone 1 ECM down to furnace module...

Data is passed via CAN lines on telephone cable to command either of the 3 units or all 3 to run as selected...

[bobbecky]

On page #9 of this manual, the layout of the cable that looks like a phone cable is shown. This is the cable that ties the thermostat to the first A/C unit, and then again from the first A/C unit to the second A/C unit.

https://www.manualslib.com/manual/1061939/Dometic-541815.html#manual