I have a 2006 screw with the tow package and the passenger side tail blinker/ brake lights on the trailer aren't working. The bulb has two filaments with one being for the blinker and the other for running lights. The running light works perfect but not the blinker. All wiring is factory that includes both truck and trailer. I tested the wiring with the trucks four and six way light plug. The funny thing is that it works on my dads 03 E-150. So what are your thoughts?

 

Try fuse #36 (trailer tow right side turn/stop lamps) let us know what you find.
Good luck!

 

Do you have access to another trailer? If so see if the problem follows to it. If it does the problem is in your socket. That's what it sounds like. Maybe this will help; How to Wire your Car or Truck for Trailer Lights

 

Why Not get a test light (very inexpensive) and check at the Truck plug. That will identify where the problem lies Turck or Trailer

 

had the exact same problem it was the fuse !!!!!

 

Your right it was the fuse, I didn't think their were more then one fuse for the lights. thanks