Originally Posted by
Slickmullet99
Both lights have a ground off of them and then there is a ground at the harness attached to trailer.
The trailer plug has a ground wire that connects to the vehicle ground. That ground is attached to the trailer frame near the tongue. I cut that ground wire and spliced in two ground wires and ran one down each side of the trailer and spliced them to the ground wires coming off the lights. These are also attached to the frame near the lights.
Ergo all lights are grounded to the trailer and the vehicle through a grounding "system." So if the ground on the frame on the Drivers side corrodes through, that light is still grounded to the tongue ground, the passenger side ground, and the vehicle ground. Make sense?