furnace wiring problem

[tiffensdad]

Long story short. The furnace in the new TT comes on when you plug in the rig to shore power or take out the fuse and reinstall it.Tstat has no effect on the furnace.

I did some checking and finally found the wire from the Tstat designated for the furnace goes up to the AC but is not connected to anything. The wires from the furnace that also ran to the AC were bound together. (That would be a blue and blue/white wire off the Suburban furnace Separating those stopped the furnace from coming on when the rig was plugged in.


More checking and find that the blue/white wire from the furnace has 12 volts all the time. the other has none. Connecting the Blue/white wire to the green wire from the Tstat makes the furnace work "normally"..(I have not had the time to do a complete testing of all the possible scenarios for a furnace.)

But I still have the Blue wire from the furnace that is not connected to anything. I have no idea where it goes. I tried running it to ground, but that resulted in the wire heating up. So I don't know at this point what I need to do. All the wire diagrams I have looked at have been of little value to me.


I did test these wires for continuity and they all seem to be single runs to the stated points.

I posted links to photos but that didn't help much as they went nowhere so I removed the links.. I have them if anyone wants to see them.

Thanks,
Really need some help on this one.

[BFL13]

This might help

https://www.youtube.com/watch?v=2qKUicCWFZ4

[dougrainer]

The 2 blue wires on the suburban
1 Blue wire will be HOT (12 volt) all the time on MOST RV's. THIS wire goes to either the AC upper control board OR goes direct to Wall Tstat. Then depending on if going to the Wall Tstat, the other Blue wire will connect to a different color(usually) going to the wall tstat. When you call for Furnace the 2nd blue wire is closed to 12 volt with the original 12 volt blue wire at the tstat. This sends the 12 volt signal to the furnace to start a run cycle
IF the wiring goes to the Roof AC then the 2 blue wires go up to the Roof AC control board and the Furnace relay ON the Roof AC control board closes and sends that 12 volt signal to the Furnace to run.
Since it appears you have determined that the Furnace wiring goes to the Wall tstat, forget the AC control board.
The WHITE wire coming out of the wall tstat is connected to the Cold(Dead) blue wire at the furnace. Doug

[tiffensdad]

BFL13 wrote:
What is the brand and model of the Tstat? The wiring varies by brand and model.

It is an AIRXCEL from RVP. Model number 9430*338

[BFL13]

What is the brand and model of the Tstat? The wiring varies by brand and model.