My brake lights and turn signals work .the strange part is that I just had a brake line go on my truck I replaced it but still the same no running lights when I turn the head lights on no camper tail ...
If it were a Ford seperate fuse for rv tailight/running light (same circut) in the engine bay fuse box. Which feeds the plug. The plug has single feed for camper tailight/running lights so as mentioned a bad connection or loose wire there will kill camper.