Couple items for you.....
First, go to the Thor Owners Resource site and you can download every document they have for your rig. It will include some electrical information but not every detail. I have had to do a lot of my own digging to figure what they have done in terms of electrical with some of the circuits.
The next thing to try to eliminate that they used the Ford 12V for your lights..... pull the negative cable off your chassis battery and see if you still have your overhead lights. If you do, then you know there has to be a fuse off the house battery circuits. If the lights go off, then you can look at the Ford fuses.
Thor is great about hiding fuses! They didn't even label the 12V Fuse side of my WFCO panel. I had to email support and they sent me the attached legend. You can see there isn't a lot of detail in some cases.
Thor was correct telling you that not all of these things are wired the same. It depends who is doing it and when. I have seen a lot of rigs that used wire nuts and they did a terrible job with the connections. My rig was done with WAGO connectors and the wiring was a little better than some I have seen.... but still far from what I would call well done.
I have found hidden fuses in the cubby hole behind my awning and entry light switches. I have also seen hidden fuses in the rats nest of wiring behind my WFCO panel / converter. There is no documentation on what circuits those fuses control. I should probably start pulling those hidden fuses to figure out what they control.... or I will be doing that when I eventually have an issue with a circuit.
I found a blown fuse under the hood (hidden under the engine coolant reservoir) by accident when troubleshooting another issue. It was for the Emergency Start Relay that ties the house batteries to the chassis battery in case you can't start the rig. It was bad from the day I picked it up because the chassis battery was dead during the PDI and the Emergency Start didn't start the engine. They blamed it on all the batteries needing charged but it was the fuse that wouldn't let the Emergency Start do it's job.