Hello! I just pulled a flat bed off that was on my 99 2500 CTD when I bought it and am going back to a regular 8' bed. The wiring harness from about the rear axle back has been cut and a new harness with two plugs for the flatbed spliced in. Yesterday I pulled a harness from the rear axle back off a 1999 1500 that had the 7-pin trailer package. According to the service manual, I don't see a differentiation between the wiring for the 1500 or 2500 of the same year.

I will upload some photos, but on the truck side of the harness, I have two extra wires. There are two DarkGreen/Red wires and two Brown/Red wires on the truck side. On the harness side behind the axle I pulled yesterday, there is only one DarkGreen/Red wire and one Brown/Red wire. I am having a hard time figuring out what to do with this wiring diagram and wondering if I just need to splice two DG/RD into one and two BR/RD into one and call it a day?

Thanks for the help, I'll upload some photos and those parts of the wiring diagram that mentions these wires.

This is the axle back portion of the trailer/tail light harness

This is the truck side of the trailer/tail light harness

 

I suspect they are just duplicates. Take a look at the connectors that are supposed to be there, and see what dodge did with them originally.

Nope, no difference between 1500, 2500, or 3500 when it comes to wiring.