Second Non-Ducted AC Question

ExT, I'm relying on memory about that old (1983 vintage) Coleman Mach 13500. There was some kind of diverter with a lever. Had to remove the plastic inside cover to access it. Might have only served to block discharged air from one set of louvers so it all went out the other. I remember finding it, thinking it interfered with something I wanted it to be doing better, and disabled or removed it.
OP, You can go to the Dometic site and get the wiring diagram. There may be one on the unit, once you remove the plastic cover. I know there's one there on Coleman. If your complaint is that the fan is running when the compressor is not, I'm sure you could wire it to the Fan was controlled by the Thermostat just like the Compressor is. That said, you will DRAMATICALLY increase the startup AMPS when the Thermostat kicks both Fan and Compressor in simultaneously. You might even want to install a Relay to handle the load so it doesn't impact the Thermostat. From there, you could devise a circuit to start the Fan shortly before the Compressor. The Ducted units with Wall Thermostat have a Control Board that can do all these tricks. At least in Coleman, the non-ducted machines have only a Mode Select (Low/High Fan and A/C with Low/High Fan) and a Thermostat with a graphic representing Cool and Cooler. Your Dometic might represent Cool and Cooler with Numbers like "68" as you mentioned but Coleman doesn't. That's what threw me off when I read the OP and thought maybe it was a non-ducted WITH wall t'stat.
About all I can add is:
1. I'd try to get used to it, and
2. Non-ducted also does NOT have a "freeze sensor" to keep from frosting up and cutting off air flow. Running fan on High helps avoid frosting.
3. Again Coleman, but our 15000 Mach unit has a two-speed 1/3-HP blower motor. We call the two Fan Speeds "Very Loud" and "Even Louder."

An RV roof air does not draw air in from the out side and the compressor has nothing to do with the circulation of air from the fan.
Sounds like you may have an air leak between the evaporator coil and condenser coil areas of the sheet metal baffles up on the roof.

No, I do not have a wall thermostat. It has a control knob. I do not have the model number handy. It is a 13.5 Dometic Brisk Air 2.

Usually a non-ducted RV A/C does not have a wall thermostat. But yours does? If it does it probably has a control module where you might be able to alter the fan function. What's the Model Number? Maybe there's a manual on www.bryantrv.com. Our non-ducted Coleman has control knobs on the unit itself, and does not "officially" exchange air from outside. I imagine there's some leakage, though. We had an older Coleman that I believe DID have a little "outside air" passage that could be turned on and off.