Hi all I have a 2005 f350 6.0, my trailer running lights aren't working. I have check fuses and replaced the fuse panel but still no power. I am thinking of running a wire from the truck tail lights to the plug anybody see any problems with this idea?

 

Take your multi meter or light tester and check the plug first at the back of the pickup first. I could very well be a bad plug.

 

Already done that I got no power at the wire that feeds the plug. Brown-white I believe is the running light wire.

 

Had a similar problem and it turned out to be a fuse in the block under the hood. I don't recall which one it was though.

 

Loose wires at connector, Bad auxiliary battery etc.

 

Trailer light fuses are on a separate circuit on mine and the fuses are located under the hood.

If it were me I would avoid cutting into the truck wiring and fix the trailer light circuit instead. The "problem I see with the idea" of splicing into the truck lights is that if there is a dead short you could introduce the same fault into the other light circuit.
Then you get to fix 2 problems. If you don't have time to fix it right the first time, do you have time to fix it twice?

 

Your right Sam I am, I'll try and test it at the back of the panel at the relay

 

Mine was tested at the fuse under the hood and determined to be a bad circuit.
Then, it was discovered to be the auxiliary battery was bad and was causing the trailer running lights to malfunction. I replaced the battery (Ford did, you can't even see it) and then the circuit was good.

 

problem solved!
The loom had rubbed through the wire about 10" after the conecter under the hood. Right where the cable sheild starts.
Glad I found it!