We had a fire about 2 yrs ago. We were driving along, happy go lucky. I got up to DH a bottle of water. I told him I smelled something hot. We have a Class A, and I did NOT smell it while sitting in the co-pilot seat. We looked around and didn't see anything. I only smelled it back around the kitchen area.
We stopped at a red light and I saw smoke coming up outside the driver side window. DH pulled over. Something went wrong with the brake/wheel bearings. It overheated and broke out in flames. DH looked up and asked where the fire extinguisher was.
This old lady was waddling pretty fast to get the fire extinguisher. Never leave home without one. We ended up spending the night in a repair shop. All in all we were very lucky.
After the discussions on here of ppl getting trapped, I will have a second fire extinguisher back in the bedroom area before we go anywhere again.
I'd imagine a fire could start from any one of hundreds of possibilities.