Personally most issues with trailer wiring comes from faulty grounds.
For me I run individual ground wires from one junction point for each circuit. From your junction box I would run a ground wire to the right turn/brake light
assembly. Another ground to the Left turn assembly. A separate ground to the 12 volt side of the fridge
Every frustrating 12 volt DC issues were caused by wires spliced together like a tree branch or from everything running a ground to the frame using the frame as a common ground point. Things get old, exposed and corroded.
This costs more money but 10 years from now if you have issues you have a single wire run to sort out rather than 1 main branch circuit with 10 different splices and /or scotchlock connectors.
When I put my load center in for 12 volt dc I ran one pair of wires to each item. One ground and one power and one fuse. This way when the trailer goes to someone else and they blow a fuse its a simple easy fix effecting no other circuits.
Just remember to label both ends of the wire runs. I am not getting any younger and anything I can do now not to have to fight with later when my memory gets worse and life much more frustrating is a good investment.
Barring an accident this 30 year old trailer will out live me so a little extra effort will pay off for someone.