Ground questions

[Urch]

Bought a '14 Laramie few weeks ago and checking it out there was a coil of wire u der the box so I used it to add some lights around the bed. Two wires, hot ground. If I use the frame as ground it blows fuse. If I use ground wire it works fine. What gives?

 

[JohnnyMac]

Could be that the wires are powered by a separate power supply that has a floating ground. Do you have a meter that you can check what exactly the voltage is? I would check it across the two wires, then check it from each wire to the frame. The voltage across the wires, should ideally be exactly the same as from hot to the frame.....+/- a couple millivolts. If both wires show a voltage of some sort when checked to the frame, then it has some sort of floating ground, or there is a power supply that is producing that voltage and it's probably not 12v. Or its PFM.