I might be off topic but, I had issues with our furnace not igniting, the fan would run but no burner. Sometimes it worked, sometimes not? Thought it was the thermostat, it wasn’t. There should be a black reset toggle switch inside the exterior access cover, try that to see if it will ignite a little better? Ultimately ours had a faulty limit switch. The furnace was replaced curtesy of LL. Works perfect now.
The external furnace intake/exhaust is located on a black panel that's held on with 4 screws....probably #2 square drive. Remove that panel and you'll be into the furnace burner area. On the inside of the camper opposite the external part will be an access panel of Azdel. Remove that and you'll have access to the blower area for cleaning. It's a mess because LL apparently didn't own a vacuum cleaner.

I hope a complete inside/outside cleaning will help it run reliably. All of the RV furnace manufacturers have their owner's manual on-line. Some are snotty and don't post the full repair manual, but it's findable for them too.