I have a 2002 Super Crew XLT 4X2 w/ factory tow package. My new boat trailer utilizes a reversing solenoid for only backing up. I've been using the lock-out pin thus far to accomplish this but am growing tired of using this method. The trailer wiring has a 5-pin flat pak connector with a separate blue wire for connecting to the truck's reverse light. However, a trailer company said all I need is a 7-pin round to 5-pin flat connector adapter because the truck is already wired to accomodate this. I tried that and it doesn't work. Can someone provide a "clean" way to hook up this blue wire to the back-up light ?

 

Dumb question, is the relay in the fuse box to active the reverse light circuit on the trailer harness? If you take a test light or DMM to the reverse light pin on the trailer connector with the truck in reverse does it show voltage? I don't have a diagram in front of me right now but I think its the center pin of the 7-way. If you have voltage on the correct pin in the 7-way socket on the truck with the truck in reverse, plug in the adapter and see if you have voltage on the 5th pin/blue wire. If not there is probably a wire in the 7-way to 5-way converter that is not connected to the correct pin on the 7-way socket. I think you can disassemble the converter and change the pinout to match the socket on the truck.