Trailer Backup lights not working, and Trailer brake lights go off when I put truck in reverse... I just re-connected my 5-pin pigtail, wanted to tidy it up and put heat shrink tubing on (it looked crappy with old electrical tape wrapped on it). Everything else works properly - brake lights, turn signals, running lights/markers.
I use an adaptor for the 5-pin flat connector to the round receptacle on the truck. Trailer has 6 wires coming up to the harness - two brown (I believe it's one for each side of trailer for tail and marker lights), one green and one yellow (left and right turn/tail lights), and two red (which are actually blue, one is spliced from the blue coming off brake solenoid and one is spliced to reverse lights blue wire). The attached picture is "before", I have double/triple/quintuple checked that the "after" current connections are the same, and are solid.
The two brown trailer wires are connected together to the brown wire from pigtail; green and yellow to green and yellow; and the two red (blue) are connected together to the blue from pigtail.
The pigtail has a white ground wire that was/is not connected to anything. I don't understand why there is a ground coming from the harness that wouldn't be connected to anything? It was just wrapped under the tape.
To the best of my knowledge, everything was working how it should before I re-did the connections.
Any ideas what would cause the issue(s) with the backup lights please? Thanks!