chevyman07

When I hook a trailer to the truck using a 7 pin connection, the left (driver) side blinker and stop light on the trailer don't work. All the other trailer lights and electric brakes work. Ground is good. The truck lights all work. I checked all the bulbs (good) and then started tracing the wires back through the trailer and truck. The yellow wire is the left blinker and stop light, and this wire is not getting power at the truck harness. I traced that wire back to a connection near the fuse box. Yellow wire is not getting power here either. All other wires in the bundle are powered properly. I can't find a fuse specifically for the left side trailer lights. Does anyone know which one it is covered by? So, I pulled every 10, 15, 20 and 30 amp fuse and tested them. All tested good. So if no fuses are bad, but just outside the fuse box the yellow wire is not getting power, what do I do? I'm at the end of my electrical knowledge and don't know what to check next. Suggestions, thoughts? Thanks.