Horn Assembly problems of the 1997 GMC Sierra

I was returning to albuquerque, nm from amarillo, TX pulling a trailer with an antique stove in my trailer. Immediately before leaving amarillo, I had my friend check all of the trailer lights and their functioning. They all worked fine. I took the scenic route through hereford entering onto interstate highway 40 at santa rosa, nm at about 9:00 pm - it was dark. Before long a semi passed me an he flicked his headlights. I wasn't sure what the flicking of his lights meant. About 30 miles later a semi passed me right before a big hill. He immediately lost his speed going up the hill and in a few moments I was right behind him. I did not want to pass him since I was pulling the trailer, so I stayed behind him as he continued to slow down to around 55 mph. Another semi approached very fast from behind and there were other cars in the fast lane. At the last second the semi swerved around me to the left and passed me and honked his horn at me. He narrowly missed running into the rear of my trailer. This time I new something was up, so I pulled out at the clines corners exit and stopped as soon as I could. Sure enough, all of the lights on the trailer were out. I pushed on the wiring coupler and they all came on. I went about 10 more miles and pulled off at another exit to check the lights. They were still on, but I pushed the coupler together to help ensure it was working loose. All of the trailer lights went out and no matter how much I played with the coupler they would not come back on. I spent the next 45 minutes laying on the cold pavement with a flashlight cutting the wire to the license plate light on my truck and splicing in some wire to get the lights on the rear of the trailer to light up. I also had to create a new ground wire. The coupler system is made by velvac near milwaukee, WI. I would be happy to send you the leftover junk parts. Dan.