I’m in a 2013 stralis hiway this week, one side of the trailers side lights have decided to stop working… The trailer rear cluster still has brake lights and indicators but no s/l. Im looking for a fuse but cant find one anywhere im the fusebox or seemingly on the trailer either. There must be trailer fuses on the truck somewhere surely?
Have you tried changing the primary electrics suzy first? There’s separate feeds for left and right side on it, not just one feed for all sidelights.
If you’re not an owner driver call the transport office and make it their problem.
I like Mercs for this reason as they tell you what fuse is what on the box panel. That doesn’t help you though… sorry. 
Thanks for the replies, unfortunately in the west of Poland currently so no chance of giving it to the office to sort out, but regardless managed to sort it today in the day light. Broken spade connector on the inside of the socket on the trailer, I actually don’t think there is a fuse for the trailer lights on the unit…
194m3:
Thanks for the replies, unfortunately in the west of Poland currently so no chance of giving it to the office to sort out, but regardless managed to sort it today in the day light. Broken spade connector on the inside of the socket on the trailer, I actually don’t think there is a fuse for the trailer lights on the unit…
Glad you got it sorted. Day light always makes things easier. Nice one.