Trailer lights acting very weird any help?

Try a different pig tail if you have access to one.
That will eliminate the most simple problem of a broken/frayed ground inside the wiring.
Could be bad prongs, too.

Start there.

If that doesn't work, it's likely a ground issue somewhere on the trailer.
Almost always is.

If the tractor is correct, then it's the conduit (pig tail) or the receptor.

 

Bad ground does funky things.

 

I usually open up the trailer prongs a bit with a knife or screwdriver and that fixes the issue.

 

I used to do that until you break half a prong off. We used to put a big paper clip in the plug. Cop will write you up for that today.

 

At that point, the prongs have been messed with so much, so the unit would definitely need to be replaced.

 

I've learned that just pushing a narrow bladed screwdriver into the slot works much better than trying to twist it. Just a bit of inward force but no actual torque. Too many "DOH!" moments with twisting and breaking....