RV electric power, half not working

I had the same problem awhile back in mt travel trailer. I could trace it to the GF Plug as everything hooked upto it was out. Then every so often it would start working. I figured the GF plug was bad so I bought a better one that has the green light. When I was switching the plugs one of the stripped wires broke. It must have been hanging by a thread or making some contact. What had happened was the guy wiring my trailer had put too much pressure on the wire strippers and gone through nearly the entire wire. It finally let go. I installed the new plug and everything works fine.