Rear lights acting like they can't find a ground

A multi tester is useful for solving electrical problems , No one uses them or is willing to learn how so there's nothing I can do to help

make sure you have right bulbs in them

Things to check, crosscircuited bulbs, burnt spots inside the lamp sockets especially around the ground wire, the tail light wiring ground itself.

I've changed all bulbs, patched in a new ground from before the gas tank to the very end of where pig tail connects to last harness. Last harness meaning where it t's off to left and right tail lights. That made everything work for 2 seconds. Then i blew a fuse and after replacing fuse, blinders no longer work in front or rear. License plate lights stopped working. But now i do have tail lights and break lights and have them at the same time

Then you’ve wired something wrong or still have a cross circuit. And replace your positive feed wire in your tester.

Do you have a trailer plug? That’s another place to look for cross circuit.

I took the trailer plug out first sign of problem, thinking that was it. It's just a plug and play one. And I thought the same thing about thinking the tail lights were looking for a ground. But then i changed the ground and then gained some functions and lost others? I'm scratching my head. Originally i thought worst case I'd just run wires from fronts to rears. Silly yes, but a fix is a fix in sorts. Now that isn't an option. I'm so out of sorts I'm feeling certain that I've caused more problems trying to diagnose original problem. Everything is so brittle and I'm so heavy handed. I've got a can of worms. And let's face it, it's a 1991 ranger. I'm about one more attempt from it just becoming a truck that is used only during day time. Thanks in advance fellas for the help

This can be a real nightmare to a novice, I’ve rewired many rigs in my past, what worked best is getting good wiring diagrams, the colors and size of wiring you need, then start at the furthest connector and do one wire at a time, solder and shrink wrap. If that didn’t fix it then from that same connector for forward doing the same thing. Once you have finished the rewire then use good plastic collet and cover the wiring that is now exposed. Yes it takes time and go slow, if you need sockets, then now is the time to replace them while your there and use the solder and shrink wrap there too, not the connectors that is supplied. Prevents problems later on.

Thank you

Lot of useless information, and commentary here. Wish someone had a good answer, since I am having the exact same issue. I'll keep you posted if I have any luck resolving this.