7 Pin Trailer Connection falling out of TV outlet

I was glad to see this thread. Our problem is that the plug won't go all the way into the receptacle in order to latch under the lip, especially in very cold or hot weather - very frustrating! We've also had to resort to bungee cording it in to make sure it doesn't come out. It's always a source of anxiety on every trip - will it or won't it plug in correctly? We've already had the receptacle replaced once, but it didn't help.