2006 Dodge ram 1500 Fuse boxes.

There may be a fuse in the plug line wire or it is not grounded.

holdon is right, it may be just that, but The only fuse box is under the hood on 2006 Ram 1500

I have gound to the plug as I have tail lights and can light a tester from the tail light wire (brown) to the ground on same plug (White). I am checking them at the 4-way at the rear of the truck with the trailer not plugged in. I traced them as far as I could under the truck until I could no longer get to the bundle. Thanks for the replu