Clayton_Cherokee

I have a 2011 Grand Cherokee with a factory towing package. Last night when I hooked up my trailer I found my brake lights and turn signals work but no tail lights. On further investigation I found there is not power to the the running light pin for either the flat or round plug. As far as I can tell one fuse controls all trailer lights. (Please tell me I'm wrong as this would be an easy fix) If it's not a fuse, does anyone know if there are known issues with a specific connection or do I just have to work from the back forward to find the first connection? All lights on the Cherokee are working fine.