1 corner of lights not working

hey guys, i would LOVE to fix this soon, since i was pulled over for it last night and spent 5 hours in jail serving for a BS traffic warrant.

Sunday, i noticed my taillight was out, so i changed the bulb. passenger side, BTW. i noticed while i was changing it, when i would wiggle the wires it would flicker on and off. decided if that didn't fix it, i would change the socket itself. Yesterday i saw it wasn't working, so i soldered in a new socket, and as i was backing out of the o'reillys parking lot, i noticed that on that passenger side, my reverse light, taillight, brakelight, and blinker light were ALL out. is there a connector/pigtail/harness somewhere where i can make sure its connected correctly? I checked all fuses and relays and couldn't find anything that would indicate that particular corner was on a different circuit than the rest. ALL other lights work fine. any information would be GREATLY appreciated. Thanks in advance guys.

What year? I don't think there were too many signal light wiring changes over the years, but I'd rather be starting from the right schematic.

91 laredo 4 door, if that makes a difference. 4.0, 4WD

After a while the connectors get corroded, they vibrate loose, and the wires start to fray. In your case though it sounds like the connection to the main ground has gone bad (all of the exterior lights are switched power with constant ground, and the grounds at the tail-light fixtures merge into a shared ground in the mini-harness). The easiest thing is probably get another tail light harness from the junkyard. Each side has a mini-harness that connects to the main harness behind the local kick panel in the cargo area. I've replaced each of mine twice.

There is a common ground in the drivers side rear inside quarter panel, behind where the spare is kept.

the harness was completely disconnected at the plug. took about 2 minutes to find that, and another 6 to re-solder the connections for the new socket i put in monday night, and everything is GTG now. Thanks for the info guys!