2016 Freightliner Cascadia Blowing fuses for the trailer running lights.

Small screwdriver bit.

 

You have a short somewhere. You will have to find it & fix it.

 

Well u could disconnect the pigtail at the trailer. Then reinsert a fuse, and see if if it still pops;

if it doesn’t, then the short is likely to be on the trailer side somewhere.

Check anywhere light wires pass through o rings/ metal, where they make bends and etc... if you’ve gone through salted roads lately, I would look up around wherever the tire spray would be. Then inspect those wires, if not covered real well, they could be ate through and wire exposed. At this point the exposed wire could be touching metal grounding out and popping the fuse.

 

yes try a different trailer. if it's specific to the trailer, open up the box on header of the trailer, chances are something rubbed through in there. Get a powerprobe and try supplying juice to the trailer manually on the correct pin, see if it pops the breaker on the powerprobe, open the box, try again, see if you can see or hear the short. Some trailers split the clearance lights so there's 2 sides that come together, then try and isolate which side it's on if it's not in the box. pray it's not hidden too bad. Chances are it's in the trailer.