12V Power for AC Thermostat in 72 Sovereign

[goobscoob]

72' Sovereign
According to the installation instructions and an older thermostat troubleshooting post I need 12v power supply for my Dometic Penguin 15k Duo Therm with CCC 2 thermostat. (120v for the main operation but somehow the 12v operates the thermostat and I dunno what else)
I've looked around the hole and I don't see anything up there.
I have this picture in the service manual for 12v Wiring;



#6 = Air Conditioner
#7 = Thermostat
There were four wires that ran from the old Armstrong to the Thermostat along that route.

I had never really looked at any kind of wiring diagram before prior to this so I initially assumed that because Air Conditioner was on it at all that meant it had 12v power up there somewhere. On closer inspection of this diagram it looks like the wires depicted from #6 -> #7 are purely the old thermostat wires.

Am I correct in assuming that;
1.) The humps in the lines that run perpendicular to that wire mean that they just cross over each other, but do not connect?
2,) Connecting lines are signified by the black dots at the intersection of the two wires?

I'm sure to some of you these are 'duh' questions but I don't know. If that's the case it seems I'll have no choice but to run a new 12v power line up there, or tie into another loop? (have an electrician do it most likely)

Any suggestions on what to do here?

I have been determined to do as much of this AC installation as possible DIY but I'm a little out of my reach here, don't want to tie into something wrong or go through a massive amount of work to run a wire if there is an easier & sound way.
Your input is always appreciated.

Regards,
M

[TG Twinkie]

You are correct about the "humps" in the wire. They only connect where the dots are shown.
Having not install a new AC unit. I am only guessing here.
The thermostat is nothing more than a switch which can be preset to a certain temperature.
In most cases the power source for that switch is the air conditioner or furnace whatever the case may be.
I would think the drawings for the AC unit would indicate this.
Since the wiring appears to be there it is a matter of selecting which wires you want to use.
If the AC. Unit also includes a heat pump. It may have a 3 or 4 wire control system. But again the AC manual should indicate what is needed.
Use an ohm meter to ring out the wires for identification.
If you could post info from the AC manual we could be more help.

[goobscoob]

Was able to score some updated installation instructions courtesy of dometic customer service.

Here is what we have regarding 12v supply;

Prep Section -> Wiring Requirements
2.) "Route a dedicated 12 VDC supply wire (18-22AWG) from the RV's converter (filtered side) or battery to the roof opening."
a.)This supply wire must be located in the front portion of the 14x14 hole
b.) Make sure at least 15'' of wire is in there

further along in the installation instructions it resurfaces;

Wiring The System (Low Voltage Connections) -> CCC2
a.) "Connect the previously run 12 VDC supply wire to the red and black wires protruding from the 14x14 hole"


Other than that there's no mention of it in the installation instructions. (other than those identical instructions for the other types of thermostats.)

The only connection between the AC and the CCC2 thermostat is the backwards telephone cable (i dunno why they couldn't just make it to where we could use a normal phone cable!) and I'm figuring somehow the 12v goes through into the AC via the supply wires and then to the thermostat via the backwards telephone cable. This is my amateur deduction.