AC mystery - where does the little orange wire go?

[Radio]

I wish this was a "fun" puzzle, but this is a real life "wish I knew the answer" kind of deal...

Opened up the filter grill on my Dometic 13.5 ducted air conditioner and happened to notice this little orange wire sticking out by itself. All the other wires have mates, blue to blue, brown to brown so on, although the mating wires are not always the same color.

There is no orange wire for it to mate to. There is no other wire of any color that does not have a mate. The little wires seem to be in a bundle or cable.

The A/C works fine.

The furnace has never worked right. For the furnace to come on an run one heat cycle a switch on the side of the furnace must be cycled on and off.

Maybe this is the problem? Where does the orange wire go?

[Jpatrickc]

It's hard to tell from the picture so I'm not sure if it is coming from the AP unit or a cable that is going out of the unit. If it's in the cable from the thermostat I would check at the thermostat and see if it is connected.

Just guessing if it could possibly be an antenna for a remote control?

Pat

[electricflyer]

Did you read that label that says "caution". You were in forbidden territory, you could get hurt. But, does that diagram give you any clues?

[Radio]

Originally Posted by electricflyer

But, does that diagram give you any clues?

I think that is all internal to the A/C unit.

[kd2iat]

Here's one possibility...

The RV manufacturer purchased a stock of cable with x number of conductors, but only ended up needing x-1 for your rig. Therefore the dangling wire. I found that to be true on two different rigs over the years. If you can locate the other end of that cable, you may well find the same dangling orange wire. Proper wiring practice suggests that unused wires should be taped back or cut away in some fashion, but a lot of RV manufacturers tend to skimp on these practices. Just pull any 110vac wall socket and examine the wiring. It ain't up to what we expect in residential or commercial wiring.

I'd pull the thermostat off the wall and see if the cable feeding it has that extra wire. It's also possible that it's in a bundle going to the furnace.

As for your furnace not be properly controlled by the thermostat, something's not connected right would be my guess. You'd probably need to have the install manuals for the thermostat, A/C, and furnace laid out side-by-side and trace out all the wiring. It's tedious and mind-numbing, but necessary. I've done several conversions of the thermostat from the standard Dometic Duo-Therms to a Hunter or other unit. Each time, I ended up tracing wires and wire colors. Seems that RV manufacturers don't always purchase multi-conductor cable that has the same wire colors as needed by the various appliances. They use what they have in stock and that can create issues for owners down the road.

[NN5I]

I googled "rv air conditioner wiring dometic" and found several Dometic manuals with wiring diagrams for various models. Each of these showed orange for a common lead to a thermostat.

On Colemans, orange goes to an overheat sensor (bimetal thermostat) that opens when the heater gets too hot. But you said yours is Dometic.

You can probably download the installation manuals for your particular equipment from Dometic. Your photo isn't clear enough to read the wiring diagram on the label.

[TXiceman]

Some A/C units have wiring to add a PV cell on the unit. There is a connection diagram next to the wires in your photo, but I cannot rear it. It should show an orange wire if it is used and what it connects to.

Ken

[NN5I]

Originally Posted by TXiceman

Some A/C units have wiring to add a PV cell on the unit.

Trying to figure out what possible function a photovoltaic cell could perform in an air conditioner. I give up, though; I'm stumped.

Originally Posted by TXiceman

There is a connection diagram next to the wires in your photo, but I cannot rear it.

Yah, I can't rear it either. Also, I can't read it.

[TXiceman]

Some units are wire to put a solar cell up top and wired to trickle charge the batteries.

Both of my Colemans have a plug up top and one below that can be connected to a solar charge controller and the battery. But the wires are identified.

Ken

[NN5I]

Originally Posted by TXiceman

Some units are wired to put a solar cell up top ... to trickle charge the batteries.

Ah so. A thoughtful solution, that, to the vexing problem of getting a circuit from the roof to the interior. I wish my two Colemans had that.

[wa8yxm]

The top of the A/C cover is an ideal place for a solar panel so why not add a charge line?

I keep wondering what this wire is about... Will keep reading till hte O/P posts "Figured it out it's the________"

[N3LYT]

I see a orange wire for a freeze protection switch for Colman AC heat pump systems.

[NN5I]

Wade, I figured it out. It doesn't go anywhere! It just stays right wherever it is.

[N3LYT]

Yes I would be very surprised if it ended up behind the fridge one day.

[wa8yxm]

Originally Posted by NN5I

Ah so. A thoughtful solution, that, to the vexing problem of getting a circuit from the roof to the interior. I wish my two Colemans had that.

They do.... if you think about it hard enough.