[chuckster57]

Originally Posted by xrated

The older camping trailers probably have the 7 conductor cable because they had an analog thermostat, but the newer ones are more likely to have a 4 conductor wire. This is because most all of them now use digital thermostats and those generally require a +12V, a -12V, and a communication (comm) wire. The +12 goes to the control box and then the control box has a terminal for th R+ to go to the thermostat. The -12v goes to the thermostat and to the control box, and finally, the "comm" wire goes from the control box to the thermostat. This is the wire that transmits the digital signal from the thermostat to the control box to tell it what to do.....heating, cooling, fan speed, etc.

So, there is a possibility that the O.P.'s thermostat cable does in fact have an extra wire conductor in it that is not being used (should be taped off on both ends...maybe). It that's the case, he could swap out the R+ wire that is bad with the wire that is not being used and get lucky. I guess I would be concerned with "what happened" to the existing R+ wire that it is not working any longer. Was it damaged? A screw or nail put through it? Pulled too tight? In other words.....are the other wires in the cable possibly damaged also and headed for failure at some point in the future? Maybe!

Myself, if there were one damaged wire in the cable, I would pull it out and pull in a new wire/cable to possibly head off future problems. YMMV!

Not to argue, but I’m working on a 2019 Solitude. Digital thermostat (AirXcel) and it has 7 wires, not all are used.