back up lights on when not in reverse

[lmabey]

So when I plug in my truck camper via the 7 way plug the the backup lights come when i turn on the headlights and the voltage drops on the hotwire out of the 7-way plug to 6 volts. I became aware of this as the house batteries were not charging as I drove or had the 7-way plug connected. When I unplug the connector the backup lights go off. Just to be clear this happens when the truck is not in reverse.

When the truck is plugged in and running with the lights off on the truck I get 14volts out the back and into the camper.

Any ideas as to what is causing this would be great?

It also shows a trailer brake disconnected message. Is there some fuse that may be blown, I can hardly read whats what on the fuse box, it is certainly set up different from the owners manual.

 

[BarryG]

Backup lights being back fed by one of the other light circuits somewhere along the line. My guess would be after the truck harness otherwise would it not do it when camper unhooked?

 

[Wayne M.]

Sounds like you have a couple of circuits shorted, including a ground. I wouldn’t plug in until your trailer wiring was checked and corrected.