I know this isn't an RV ....it's a small boat trailer....
I have a 1500 dodge and I was using a flat 4 adapter to the blade receptacle from my truck, and found that the left rear blinker wasn't working so I replaced the adapter....still not nothing so then I swapped vehicles and it worked i'm thinking it was the main blade plug in that might of working on the blade blinker.....any in put?
No, I think it is a fuse in your Dodge. You changed vehicles and it worked would indicate that it is in your Dodge. The fuse would bve the first thing to checkk. Not the Dodge's turn signal fuse but the separate ones under the hood.