Suburban Furnace

I have purchased my first travel trailer a couple years ago and last year I experienced furnace problems while hunting. The fan would turn of but the burner would not fire up. I had a somebody test it and when out of the trailer it ran perfectly. After reinstall it would run for a couple hours correctly but then stop firing up, just blow cold air.

I read another forum that made me think my issue may be the battery. Does this sound like it may be my issue? I am in Michigan and my trailer is on hunting land in Kentucky so it's not convenient to try multiple fixes.

Any info would be greatly appreciated, I am new to this world and still learning. I had no idea that the battery could be this important when on a electrical hook up.

Thank you!!