Originally Posted by CenterofFOCUS
Is there an inline linkable fuse to the license plate.
No. Corrosion in that circuit is common due to the reason you describe.
Both left and right lights share a common ground. The black wire from both lights meet at a splice and are grounded by a single lead within the tailgate. Check that ground.
Also check you are seeing 12V at the orange and black wire (with the side lights on). It's a common feed also; left (driver's side) light main power wire feeds right (passenger's side) light via a short secondary orange/black wire..