Sleeper cab, no power

I’m not sure about that truck but my truck has a fuse box under the bed it is a pro star the box is located in my driver side rear sleeper box door. It doesn’t sound like a fuse considering it comes on and then goes off my pro star has software to diagnose things like that. Yours might also but i’m thinking the switch upfront might be your issue my truck has a button up front to kill the lights in the back but the HVAC I’m not sure mine went out and I discovered I had unplugged it a little bit while putting some straps in the passenger rear sleeper box door simple fix plugged it in and good to go. Good luck and before you take it somewhere take advantage of capitalism and call around to find the best price at the best place with the best reputation

 

Jumper wire from battery terminal fuse box. 4 of them jupe one to another till power

 

As I learned today on my 2013 cascadia that was having similar issues there is module behind the panel that has the 4 way flasher switch , floor light switch and the dash dimmer switch on it .
It controls all the switches, lights inside and out and the steering wheel switches.
When it goes bad crazy things start to happen ......with mine all the exterior lights came on without the switch on .
Signal lights quit.
All interior lights quit except the 2 above the seats .
Cruise quit .
Jake quit .
Flashers quit .
Switch panel in the sleeper quit .
Freightliner in Neosho Missouri fixed it today for 391.00.

 

I was going to post what you wrote in your thread. But you were faster than me.

 

Once in a while I get lucky lol.

 

Same thing happened to my 2013 about a month ago. Here's the deal. When you run the air conditioner on those freightliners, condensation will form on the sleeper duct work and drip onto the sleeper lighting switches, shorting them out, along with the switches on the dashboard since they are all daisy chained together. This is an OEM design flaw. It also threw a check engine code on mine. If you pull out the switch housing for the 4 way flashers, the wires plugged in the top right corner (black and white if I remember) unplug them and your jakes and all switches in the front will still work and engine light goes out, your switches in the bunk will be unplugged though. Let everything dry out really good and remove your sleeper switches , pull the plugs and coat them with die electric grease, them silicone them up good once plugged back in. Hope this helps save someone money and time!

 

Had the same issue on an old Cascadia I drove for a previous employer. It was the low voltage disconnect and simply starting the truck would reset the breaker.