I'm hoping someone has come across this before. I don't make it to this site nearly as often as I would like, but when I do I always find useful information. A couple weeks ago both tail lights started to malfunction. During the day time when the headlights are off, turn signals will work until I press on the brake. Once I press on the brake, they stop blinking. Back up lights are the same. They work until the brake is pressed. At night, with the headlights on, if I turn on the turn signal, either left or right, the turn signal running light alternate on both sides on the third light in the middle of the cab is flashing also. Took it to the dealer yesterday. They didn't shed much information. Just needed authorized for 4-5 hours to investigate the issue since I had wiring tapped into the main harness running to the back for my camper. I figured I would trouble shoot a little more myself before going that route. I have disconnected the camper wiring from the main harness. Still having the same issues. Any help or other things I can check would be greatly appreciated.

The front headlights and turn signals are working fine, with or without the brake applied.