Need help 2019 cascadia sleeper lights

What did freightliner say when you called them?

 

The interior lights are no longer controlled by the switches themselves.
The switches merely tell the computer to turn on the lights.
The switches up front are all routed through the Multifunction controller which IS the four way flasher module that you push the red triangle to activate the flashers. Only the dealer can change out the module as it needs to be coded by serial number into the computer system.
Assuming I’m reading your composition above correctly, as it is hard to understand what the heck you typed out.
4 Way fulesher = 4 Way flasher ?
Fues = Fuse ?

 

What did it say in the owner's manual? Oh yeah.....like that's gonna happen. At least Google it.

 

I've had good luck on the phone with Joplin freightliner and Columbus, Oh
Just to name a few.
Heck there's been times I've called more than a half a dozen shops till I got someone on the phone either not to busy to help and or willing to.