I think the smoke was due to one of the power relays stuck closed. The wiring burns up, the smoke is sucked into the intake and somehow it makes it's way inside the RV. Very definite electrical wiring burning smell.
I had that happen to my basement air and all it took was a new relay. Under $100 repair. I'm a DIY'er so I had it fixed pretty quickly.
But I don't know what else that so called Tech did to your Coleman.
They are repairable, well designed, have repair parts available but it takes some digging to find them. Without more information on yours though, and yes, I saw a walk around video so I see yours is behind the drivers side front wheel, I couldn't really begin to guess how yours might be connected to the ducting. At least I think that's where it is.
I do know that if you get it out of it's cubby hole, there is plenty that can be done to repair it. Even some HVAC techs will work on one if you get it out first. Not all, but some.
You do need to research and find out what the brand and model number is. I assume it's a Coleman Mach Air but you don't mention the brand name. Is there a name on the thermostat too?
Anyway, enough jawin'. Here's a link to my ad free blog article
about working on one of those basement airs. I like them. So quiet, work so well. Do need periodic maintenance though.
Here's a picture of a Coleman Mach's control board with those two big black relays that went bad and caused the burnt wiring. Ebay carries a direct replacement. And the replaceable motor capacitors down low. Those are a maintenance item that should all be changed on yours. You have those no matter what brand. This is under the cover that has the model number on it, under the RVs outside grill. You can get to all this without removing the entire unit.