where does factory wiring for AC run to

[meassick]

In the factory wiring for the roof mounted AC on my 5.0, there are a number of wires that run from the roof opening to somewhere.
There is the yellow Romex 120VAC power wire that runs to under the drivers side bench to the aux breaker panel.
However, there are additional wires, see photo, a black, a red, a pair of blue wires and a grey control wire pair (has two conductors) that I cannot seen to determine where they go. Does anyone have an answer to where these wires run to?

 

[Jeremy Kessenich]

Hollo Steve, I think they are the wires for the wall mounted control for the factory installed non Houghton AC and the furnace? I think.

 

[Chamberman]

The two blue wires should go to the furnace.
The red/black pair should tie into +12 & 12V Gnd.
The grey jacketed plenum wire has two conductors inside of it and they should be running to the thermostat. The red wire was +12V and the black wire was the communication wire, both running to the thermostat from the Dometic Penguin II control box. At least that's how our 2019 E19 with the Dometic Penguin II was wired.

In our trailer a 3rd wire was run separately to the thermostat for the 12V gnd connection at the thermostat.

 

[Chamberman]

It looks like your wires are going into a ball of electrical tape. Are the Blue wires connected to the two wires inside of the gray plenum cable? If so, they're connecting your furnace to whatever thermostat you have instead of the Dometic setup.

 

[meassick]

The two blue wires should go to the furnace.
The red/black pair should tie into +12 & 12V Gnd.
The grey jacketed plenum wire has two conductors inside of it and they should be running to the thermostat. The red wire was +12V and the black wire was the communication wire, both running to the thermostat from the Dometic Penguin II control box. At least that's how our 2019 E19 with the Dometic Penguin II was wired.

In our trailer a 3rd wire was run separately to the thermostat for the 12V gnd connection at the thermostat.

You are correct, the red/black are +12V/Gnd. None of the wires in the electrical tape bundle up at the AC location are tied together.

I am not sure where the two blue wire go to, while the wires tying into the thermostat are blue, there is no continuity between the blue wires at the AC and at the thermostat. I believe that the thermostat blue wires run directly to the furnace. I do not see an unused pair of blue wires at the furnace.

I do not see the grey plenum pair at the furnace. Maybe the pair of blue wires and the grey plenum wire terminate behind the furnace thermostat location on the wall on the rightside of the bathroom, but the only way to check is to pull the medicine cabinet in the bathroom which I have previously done.

The rational for doing all this is that I want to relocate the temperature sensor of the Houghton heatpump to where the furnace thermostat is so I need to run a pair of wires from the heatpump to the new sensor location. While it would be easy to run a pair of wires in the cabinets and above the bathroom to the furnace thermostat location, it would be more difficult to run above the vinyl ceiling from the cabinet to the AC location without there being a bulge in the vinyl.

 

[Chamberman]

I just performed a Dometic to Houghton 9500 conversion this past weekend so this wiring is fresh on my mind.

In our Dometic build and I stress that because I'm not certain how Escape wired your trailer. The Pair of blue wires at the AC are tied to the contactor to turn on the furnace. I pulled those two blue wires from the Dometic control box that was located in the AC unit and just to test I shorted those two wires together and the furnace cycled on. Its possible that in builds other than Dometic they're running the blue pair directly to the thermostat, but its odd that you have a pair of blue wires at your AC unit. Are the blue wires unconnected or are they connected to other wires in the bundle?

The grey plenum cable runs to the thermostat on our Dometic build.

 

[meassick]

My trailer came AC ready, but we did not get an actual factory installed AC because they did not offer the Houghton at that time, so wiring may be a little different than in your case. I did contact Escape for clarification, but have not heard back.

In my case shorting out those blue wires at the AC does nothing, so the other end is not connected to anything (infinite resistance between the two), but I dont know where they go at this point. The two blue wires at the thermostat definately run to the furnace to control it, they definately are not connected to the blue wires at the AC

I have also not been able to determine where the grey plenum cable runs to. Best case scenario is that they terminate in the wall behind the thermostat, but I will not be able to tell until I remove the medicine cabinet to check. I will be out of town for two weeks so will not be able to check until I return.

 

[Chamberman]

So it sounds like they ran all of the standard Dometic build wiring up to the AC location, but also added a second furnace control wire pair directly to the thermostat. My assumption would be that the blue wire pair you see at the AC location is probably unconnected and tie-wrapped into the wire harness somewhere near the furnace. It may be behind a panel near the furnace, but its probably somewhere near there.

The grey plenum cable pair is probably unconnected and behind the wall near the thermostat. If they didn't need it then they had no reason to pull it through the wall.

It doesn't make sense to me that they'd pull the wires on the AC side and not at least route them close to where they would have gone on the other end in the Dometic build, but just leaving them unterminated. However it wouldn't be the first time I've tried to make sense of what a company has done only to find out they did something illogical.