LED Tail lights

[Gunner41]

Ok so I was desperate. I just got my clear tail lights and wanted the red LED's for it. Off to Autozone I go. I picked up a couple paks of the Sylvania LED's. It was supposed to be plug and play. Nope. I had to go back and get a LED flasher relay. Back to plugging them in and it still sucks. The left side is whats driving me nuts. R/S no problems. L/S either the turn or the stop but not both. I switched them around so it seemed that the control board was bad cause now the r/s had the problem? I actually had a new one so tried it (after switching it back) same problem? I put the old bulbs back in and no problems anymore? SO its not the board, Not the relay and I switched bulbs around multiple times and they all work. Searching the internet seems like all these people are switching the whole assy and not just bulbs. I have heard that when you switch to LED's that you need to ground each one separately? Im also thinking that there might be something wrong with my harness or connectors? ugh Oh sorry its a 1997 3500 CC/DW and no problems with any of the sides or front LED's r the HID's as well???