Turn signal not flashing

You say the brake/turn signal on the rear of the rv is not working. Are the trailer lights all working correctly? Take the left rear bulb out of the rv and use a simple test light to check to make sure there is power there. You do not say how you changed the plug out. It sounds like you may have broken the wire when you connected the new plug. Also make sure that the new plug is functioning properly. I have a variety of plug parts I use when requiring things. If you have an old trailer end connection with bare wires, plug it in and test each bare wire that it is functioning properly. But you can simply ground one end of the test light to the ground and touch the various ends to check that power is getting to each point. I use two simple probes with my test light and a steady hand. Also check your rv fuses for a specific fuse for the rear lights, I found my chevy has some fuses in the engine compartment I did not realize were there until having similar issues. They were right in the fuse box but I did not realize they were wired that specific on what they controlled. When you figure it out, please post your solution.