Help...Factory trailer wiring

I have the standard 4-prong trailer plug on my 04 dbl cab. This appears to be a factory harness. The 4-prong connector is about 4 foot long and plugs into another connector, which then runs toward the front of the truck. All of the wires are enclosed in the black plastic conduit. My problem is the brakes lights and right turn signal aren't working. I have no power to the brown & yellow wires. Are there a fuse somewhere controls these? I haven't towed much since purchasing the truck last year and dont remember if they were working last year or not. I have not seen a converter anywhere, if that's important.


Thanks