Need help with furnace

[Dottie56]

Hello- I have a 2019 Forest River Ozark light 1650 BH. I have a lithium battery that is fully charged and when I try to turn on the refrigerator, the furnace goes on- it won’t shut off. I also have no thermostat because work was done and got taken out and not replaced.. I tried to pull some fuses but that did not stop the furnace from continuing. I went outside and opened up the panel and I don’t see any kind of shut off switch. It is a suburban model. If anybody can guide me so that I can run my refrigerator and lights without that happening, it would be great. I do not know why it does this and I have messed around with the fuses and it still stays on.

 

[MNC]

I think you need a termostat I cant see how it will work without.

 

[Holdmybeer]

The thermostat wires may possibly be shorted. Try pulling the wire nuts off and separate the leads.

 

[MNC]

they said the thermostat was removed

 

[Rosy]

they said the thermostat was removed

Yeah, how did they leave the wires?

 

[Earl1412]

I hope this will help you as I don't know what model number your furnace is. This was compiled from my search engine.
Suburban RV furnace wiring diagrams typically feature a 4-wire harness connecting the furnace to the trailer's 12V DC power and thermostat. The standard color code for most models (such as the SF-30, SF-35, and NT series) is:

Red Wire: Positive (+) 12V DC power from the converter or battery.
Yellow Wire: Negative (-) 12V DC ground.
Two Blue Wires: Connect to the thermostat. These wires complete the circuit for the time-delay relay to initiate the ignition sequence.
Common Wiring Configurations
Thermostat Connection: The two blue wires from the furnace connect directly to the two wires coming from the thermostat. These are often bell wire (e.g., red/white or black/white) in the trailer harness.
Power Connection: The red wire connects to the positive side of the 12V system (often through a fuse or circuit breaker), and the yellow wire connects to the chassis ground or negative bus.
Galley Kill Switch: Some installations include a galley kill switch that interrupts the 12V power or the thermostat circuit to shut off the furnace.
Troubleshooting & Diagrams
If the furnace fails to ignite, common electrical causes include a faulty time-delay relay, a failed circuit board, or incorrect wiring at the thermostat. To verify connections, use a multimeter to confirm 12V DC between the red and yellow wires at the furnace connector.

For official schematics, consult the Suburban Furnace Service and Training Manual or model-specific installation guides available from manufacturers like Airxcel or dealers such as PDX RV Wholesale. Diagrams vary slightly by model (e.g., SF vs. NT series), so always verify the specific model number on the furnace rating plate.