2013 Landmark San Antonio furnace not working

[Razorbackfan]

Worked fine up til I left CA in June. I didn’t try it when I got here in TX but when I tried to use in couple weeks ago it immediately blew the fuse.
My thought is TX critters decided to build a home but how to access that area? I’ve opened my basement wall and I see the box with the hoses coming out but where do I access the right area?
I called a mobile RV tech and he wanted $60 plus $150 an hour to even look.
Worst case scenario is I use electric heat until I move first week of Jan back to Florida where I can drop it off to Camping World who said they would diag and clean if needed for $80.
If it’s easy I would like to knock it out on the road so I can use propane again.
Also was there a specific type of furnace in these units or did they tend to use whatever?

 

[danemayer]

Your furnace is most likely a Suburban SF42.

If the failure symptom is that it blows the fuse in your main fuse panel in the coach, there's probably a shorted wire.

When the thermostat signals the need for heat, it triggers a relay in a control box that's probably under your kitchen air conditioner return (unless you have the Whisper Quiet, in which case I'm not sure of the location). That relay sends 12V DC that comes out of the fuse, and goes to the control board on the side of the furnace. The 12V immediately powers the blower motor but also powers the control board.

A short is likely at the control board, or at the blower motor. Both of those can be accessed from outside by removing the 4 screws around the cover and sliding the cover off the exhaust vents. Check for insects, leaves and other stuff in the exhaust vents while there. The 1/2 cylindrical shroud covers the blower motor and IIRC can be removed with one or two screws.

There are probably wire nuts along the top of the furnace, joining the furnace wires to the wires coming from the control box relay. That's also a good place to look for exposed wires that might be shorting to metal.