Into the rear bumper harness for the 110v plug in the bed?
Mine was also unplugged from the factory. I noticed the cable hanging but didn't look into it till I noticed the bed receptacle not working. By the time I went to plug it in, the bumper end was corroded and dealer wouldn't warranty it. The writer was an idiot, 3 other people came up and teamed up on me and all claiming it was because of corrosion and that isn't covered. I tried explaining it should've been caught during PDI but they claimed it was my fault for not noticing it before it was corroded. It definitely should be covered. Worst part is I worked at this dealership as a tech for 7 years but couldn't find anyone I knew to explain the case to. Ended up buying the bumper pigtail and fixing it myself. This was all a couple months ago. Found out a couple days ago that writer was fired for being an idiot.