Having trouble chasing down bad wire,Ithink?

[GOPAPA]

I have a flat 4 wire hook up for a utility trailer on my 06 silverado and want to know if anyone can tell me if the running lights to a trailer is on the same fuse as the running lights of the truck .

All I am comming up with is,,it being tagged in with the back up light on the rear of the cab??

It's the brown wire and should be hot when you turn on the head lights of the truck as thats the running lights. But it is not and I cannot find a fuse that has anything to do with it so far.

If any of you have any experience with these year of trucks concerning trailer wire hook ups ,,I would appreciate some feed back to maybe get my running lights operational..