Look in the files section for RV Furnace troubleshooting. PDF.
IF your Furnace blows cold air for a few seconds then quits, sounds like a sail switch.
Following the troubleshooting steps.
You need to be outside and listen for the igniter clicking while someone turns on the Furnace.
Also smell for propane near the exhaust.
Each of these is a clue that points you where to start troubleshooting.
Also, there is a red blinking light on the circuit board that blinks a code to tell you what is wrong.
The blink code is on a label nearby.
A very simple check is to swap the self resetting black 15A fuse with a regular blue 15A fuse.
The resetting fuses tend to be problematic.
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