The first thing to do is confirm that both the TV and trailer are properly wired. If you go to the Bargman web site and download the catalog, http://www.bargman.com/catalog.pdf
, you will find the connector diagram on page 38. Using a test light, determine if the tow vehicle is sending the power to the correct terminal, and only that terminal. When the left directional is on, only the left stop and turn should be hot. Same for the right. When the brake is energized, both the left and right stop and turn should be hot. The electric brake terminal will also be hot when the brake is energized. If all that is correct, set up a battery and jumper wires, and see if the trailer lights correctly.
From what you describe, the wiring on the truck is likely the problem. I assume that the pigtail that you changed was on the trailer. Am I correct?